diff --git a/owlps-aggregator/owlps-aggregator.h b/owlps-aggregator/owlps-aggregator.h
index 0060b59..ae13778 100644
--- a/owlps-aggregator/owlps-aggregator.h
+++ b/owlps-aggregator/owlps-aggregator.h
@@ -7,8 +7,6 @@
 
 #include <owlps.h>
 
-#define DEBUG
-
 
 /* Arguments & program configuration */
 #define OPTIONS "Aa:c:C:f:hi:k:K:l:o:p:t:vV" // getopt string
@@ -21,6 +19,14 @@
 #define POSITIONER_DEFAULT_IP "127.0.0.1"
 
 
+/* Verbosity levels */
+#define VERBOSE_QUIET cfg_getint(cfg, "verbose") == 0
+#define VERBOSE_WARNING cfg_getint(cfg, "verbose") >= 1
+#define VERBOSE_INFO cfg_getint(cfg, "verbose") >= 2
+#define VERBOSE_CHATTERBOX cfg_getint(cfg, "verbose") >= 3
+#define VERBOSE_REQUESTS cfg_getint(cfg, "verbose") >= 4
+
+
 /* Error codes */
 #define ERR_NO_MESSAGE_RECEIVED 1 // Error when reading the socket
 #define ERR_CREATING_SOCKET 2 // Erreur when creating listening socket
diff --git a/owlps-aggregator/owlps-aggregatord.c b/owlps-aggregator/owlps-aggregatord.c
index 2232aa6..727d9ad 100644
--- a/owlps-aggregator/owlps-aggregatord.c
+++ b/owlps-aggregator/owlps-aggregatord.c
@@ -103,34 +103,38 @@ int main(int argc, char **argv)
 
   /* Wait for the threads to terminate */
 
-  fprintf(stderr, "Waiting for the monitor thread... ") ;
+  if (VERBOSE_WARNING)
+    fprintf(stderr, "Waiting for the monitor thread... ") ;
   if (pthread_join(monitor_thread, NULL) != 0)
     perror("Cannot join monitor thread") ;
-  else
+  else if (VERBOSE_WARNING)
     fprintf(stderr, "OK.\n") ;
 
   if (cfg_getbool(cfg, "autocalibration"))
     {
       // We must cancel this thread because it can be blocked on the
       // recvfrom() call:
-      fprintf(stderr,
-              "Cancelling the autocalibration hello thread... ") ;
+      if (VERBOSE_WARNING)
+        fprintf(stderr,
+                "Cancelling the autocalibration hello thread... ") ;
       if (pthread_cancel(autocalibration_hello_thread) != 0)
         perror("Cannot cancel autocalibration hello thread") ;
-      else
+      else if (VERBOSE_WARNING)
         fprintf(stderr, "OK.\n") ;
 
-      fprintf(stderr,
-              "Waiting for the autocalibration hello thread... ") ;
+      if (VERBOSE_WARNING)
+        fprintf(stderr,
+                "Waiting for the autocalibration hello thread... ") ;
       if (pthread_join(autocalibration_hello_thread, NULL) != 0)
         perror("Cannot join autocalibration hello thread") ;
-      else
+      else if (VERBOSE_WARNING)
         fprintf(stderr, "OK.\n") ;
 
-      fprintf(stderr, "Waiting for the monitor APs thread... ") ;
+      if (VERBOSE_WARNING)
+        fprintf(stderr, "Waiting for the monitor APs thread... ") ;
       if (pthread_join(monitor_aps_thread, NULL) != 0)
         perror("Cannot join monitor APs thread") ;
-      else
+      else if (VERBOSE_WARNING)
         fprintf(stderr, "OK.\n") ;
     }
 
@@ -156,11 +160,12 @@ void initialise_configuration(int argc, char **argv)
   parse_command_line(argc, argv) ;
   check_configuration() ;
 
-#ifdef DEBUG
   /* Configuration printing */
-  fprintf(stderr, "Configuration:\n") ;
-  cfg_print(cfg, stderr) ;
-#endif // DEBUG
+  if (VERBOSE_INFO)
+    {
+      fprintf(stderr, "Configuration:\n") ;
+      cfg_print(cfg, stderr) ;
+    }
 }
 
 
@@ -327,10 +332,9 @@ void check_configuration()
   if (cfg_getint(cfg, "listening_port") < 1 ||
       cfg_getint(cfg, "listening_port") > 65535)
     {
-#ifdef DEBUG
-      fprintf(stderr, "Warning! Bad listening_port:"
-              " failing back to the default value.\n") ;
-#endif // DEBUG
+      if (VERBOSE_WARNING)
+        fprintf(stderr, "Warning! Bad listening_port:"
+                " failing back to the default value.\n") ;
       cfg_setint(cfg, "listening_port", AGGREGATE_DEFAULT_PORT) ;
     }
 
@@ -338,10 +342,9 @@ void check_configuration()
   if (cfg_getint(cfg, "positioner_port") < 1 ||
       cfg_getint(cfg, "positioner_port") > 65535)
     {
-#ifdef DEBUG
-      fprintf(stderr, "Warning! Bad positioner_port:"
-              " failing back to the default value.\n") ;
-#endif // DEBUG
+      if (VERBOSE_WARNING)
+        fprintf(stderr, "Warning! Bad positioner_port:"
+                " failing back to the default value.\n") ;
       cfg_setint(cfg, "positioner_port", POSITIONER_DEFAULT_PORT) ;
     }
 
@@ -357,50 +360,45 @@ void check_configuration()
   // aggregate_timeout //
   if (cfg_getint(cfg, "aggregate_timeout") < 0)
     {
-#ifdef DEBUG
-      fprintf(stderr, "Warning! aggregate_timeout cannot be negative:"
-              " failing back to the default value.\n") ;
-#endif // DEBUG
+      if (VERBOSE_WARNING)
+        fprintf(stderr, "Warning! aggregate_timeout cannot be negative:"
+                " failing back to the default value.\n") ;
       cfg_setint(cfg, "aggregate_timeout", DEFAULT_AGGREGATE_TIMEOUT) ;
     }
 
   // keep_timeout //
   if (cfg_getint(cfg, "keep_timeout") < 0)
     {
-#ifdef DEBUG
-      fprintf(stderr, "Warning! keep_timeout cannot be negative:"
-              " failing back to the default value.\n") ;
-#endif // DEBUG
+      if (VERBOSE_WARNING)
+        fprintf(stderr, "Warning! keep_timeout cannot be negative:"
+                " failing back to the default value.\n") ;
       cfg_setint(cfg, "keep_timeout", DEFAULT_KEEP_TIMEOUT) ;
     }
 
   // check_interval //
   if (cfg_getint(cfg, "check_interval") < 0)
     {
-#ifdef DEBUG
-      fprintf(stderr, "Warning! check_interval cannot be negative:"
-              " failing back to the default value.\n") ;
-#endif // DEBUG
+      if (VERBOSE_WARNING)
+        fprintf(stderr, "Warning! check_interval cannot be negative:"
+                " failing back to the default value.\n") ;
       cfg_setint(cfg, "check_interval", DEFAULT_CHECK_INTERVAL) ;
     }
 
   // ap_keep_timeout //
   if (cfg_getint(cfg, "ap_keep_timeout") < 0)
     {
-#ifdef DEBUG
-      fprintf(stderr, "Warning! ap_keep_timeout cannot be negative:"
-              " failing back to the default value.\n") ;
-#endif // DEBUG
+      if (VERBOSE_WARNING)
+        fprintf(stderr, "Warning! ap_keep_timeout cannot be negative:"
+                " failing back to the default value.\n") ;
       cfg_setint(cfg, "ap_keep_timeout", DEFAULT_AP_KEEP_TIMEOUT) ;
     }
 
   // ap_check_interval //
   if (cfg_getint(cfg, "ap_check_interval") < 0)
     {
-#ifdef DEBUG
-      fprintf(stderr, "Warning! ap_check_interval cannot be negative:"
-              " failing back to the default value.\n") ;
-#endif // DEBUG
+      if (VERBOSE_WARNING)
+        fprintf(stderr, "Warning! ap_check_interval cannot be negative:"
+                " failing back to the default value.\n") ;
       cfg_setint(cfg, "ap_check_interval", DEFAULT_AP_CHECK_INTERVAL) ;
     }
 }
@@ -445,7 +443,7 @@ int read_loop(int sockfd)
       request.y_position = owl_ntohf(request.y_position) ;
       request.z_position = owl_ntohf(request.z_position) ;
 
-      if (cfg_getint(cfg, "verbose"))
+      if (VERBOSE_REQUESTS)
         {
           inet_ntop(AF_INET, &request.mobile_ip_addr_bytes,
                     mobile_ip_str, INET_ADDRSTRLEN) ;
@@ -480,11 +478,9 @@ int read_loop(int sockfd)
                   request.direction
                   ) ;
         }
-#ifdef DEBUG
-      else
+      else if (VERBOSE_CHATTERBOX)
         fprintf(stderr, "Request received from AP « %s ».\n",
                 owl_mac_bytes_to_string(request.ap_mac_addr_bytes)) ;
-#endif // DEBUG
 
       got_request(request) ;
     }
@@ -519,9 +515,8 @@ void* monitor_requests(void *NULL_value)
   owl_request_info info;
   int sockfd;
 
-#ifdef DEBUG
-  fprintf(stderr, "Monitor requests thread launched.\n") ;
-#endif // DEBUG
+  if (VERBOSE_WARNING)
+    fprintf(stderr, "Monitor requests thread launched.\n") ;
 
   sockfd =
     owl_create_udp_trx_socket(cfg_getstr(cfg, "positioner_ip"),
@@ -565,14 +560,10 @@ void* monitor_requests(void *NULL_value)
               // If the timeout is reached
               if (sub > aggregate_timeout)
                 {
-                  fprintf(stderr, "* Timeout reached.") ;
-#ifdef DEBUG
-                  fprintf(stderr, " sub=%"PRIuFAST32" >"
-                          " aggregate_timeout=%"PRIuFAST32"\n",
-                          sub, aggregate_timeout) ;
-#else // DEBUG
-                  putc('\n', stderr) ;
-#endif // DEBUG
+                  if (VERBOSE_CHATTERBOX)
+                    fprintf(stderr, "* Aggregate timeout reached:"
+                            " %"PRIuFAST32" > %"PRIuFAST32"\n",
+                            sub, aggregate_timeout) ;
 
                   // Print mobile MAC address to the output file
                   owl_mac_bytes_to_string_r(request_ptr->
@@ -657,14 +648,10 @@ void* monitor_requests(void *NULL_value)
             {
               request_list *request_tmp = request_ptr ;
 
-              fprintf(stderr, "* Keep timeout reached.") ;
-#ifdef DEBUG
-              fprintf(stderr, " sub=%"PRIuFAST32" >"
-                      " keep_timeout=%"PRIuFAST32"\n",
-                      sub, keep_timeout) ;
-#else // DEBUG
-              putc('\n', stderr) ;
-#endif // DEBUG
+              if (VERBOSE_CHATTERBOX)
+                fprintf(stderr, "* Keep timeout reached:"
+                        " %"PRIuFAST32" > %"PRIuFAST32"\n",
+                        sub, keep_timeout) ;
 
               request_ptr = request_ptr->next ;
 
@@ -723,7 +710,9 @@ void got_request(owl_captured_request request)
   tmp_request = requests ;
   if (requests == NULL) // If the request list does not exist,
     {
-      fprintf(stderr, "Creating request list.\n") ;
+      if (VERBOSE_INFO)
+        fprintf(stderr, "Creating request list with AP « %s ».\n",
+                owl_mac_bytes_to_string(request.ap_mac_addr_bytes)) ;
       tmp_request = malloc(sizeof(request_list)) ; // create it.
       tmp_request->type = request.type ;
       memcpy(tmp_request->mobile_mac_addr_bytes,
@@ -781,7 +770,9 @@ void got_request(owl_captured_request request)
 
       if (tmp_request == NULL) // The request does not exist in the list
         {
-          fprintf(stderr, "Create new request.\n") ;
+          if (VERBOSE_INFO)
+            fprintf(stderr, "Create new request from AP « %s ».\n",
+                    owl_mac_bytes_to_string(request.ap_mac_addr_bytes)) ;
           tmp_request = malloc(sizeof(request_list)) ; // create it
           tmp_request->type = request.type ;
           memcpy(tmp_request->mobile_mac_addr_bytes,
@@ -809,12 +800,14 @@ void got_request(owl_captured_request request)
         {
           if (tmp_request->info == NULL)
             { // We already sent to the server data for this request
-              fprintf(stderr, "Request already treated.\n") ;
+              if (VERBOSE_CHATTERBOX)
+                fprintf(stderr, "Request already treated.\n") ;
               free(tmp_info) ;
             }
           else
             {
-              fprintf(stderr, "Add information to the request.\n") ;
+              if (VERBOSE_CHATTERBOX)
+                fprintf(stderr, "Add information to the request.\n") ;
               tmp_info->next = tmp_request->info ; // Add data
               tmp_request->info = tmp_info ;
             }
@@ -864,9 +857,8 @@ void* listen_for_aps(void *NULL_value)
   owl_autocalibration_hello message ;
   char ap_ip_addr[INET_ADDRSTRLEN] ;
 
-#ifdef DEBUG
-  fprintf(stderr, "Autocalibration Hello thread launched.\n") ;
-#endif // DEBUG
+  if (VERBOSE_WARNING)
+    fprintf(stderr, "Autocalibration Hello thread launched.\n") ;
 
   listen_sockfd =
     owl_create_udp_listening_socket(cfg_getint(cfg,
@@ -893,10 +885,9 @@ void* listen_for_aps(void *NULL_value)
 
       strncpy(ap_ip_addr, inet_ntoa(client.sin_addr), INET_ADDRSTRLEN) ;
 
-#ifdef DEBUG
-      fprintf(stderr, "Got a Hello message from « %s »\n",
-              ap_ip_addr) ;
-#endif // DEBUG
+      if (VERBOSE_INFO)
+        fprintf(stderr,
+                "Got a Hello message from « %s »\n", ap_ip_addr) ;
 
       sem_wait(&lock_aps) ;
       update_ap(message.ap_mac_addr_bytes, ap_ip_addr) ;
@@ -960,11 +951,13 @@ ap_list* find_ap(uint8_t mac_addr_bytes[ETHER_ADDR_LEN])
  */
 ap_list* add_ap_front(uint8_t mac_addr_bytes[ETHER_ADDR_LEN])
 {
-#ifdef DEBUG
-  char mac_str[OWL_ETHER_ADDR_STRLEN] ;
-  owl_mac_bytes_to_string_r(mac_addr_bytes, mac_str) ;
-  fprintf(stderr, "Creating AP with MAC address « %s »...\n", mac_str) ;
-#endif // DEBUG
+  if (VERBOSE_INFO)
+    {
+      char mac_str[OWL_ETHER_ADDR_STRLEN] ;
+      owl_mac_bytes_to_string_r(mac_addr_bytes, mac_str) ;
+      fprintf(stderr,
+              "Creating AP with MAC address « %s »...\n", mac_str) ;
+    }
 
   ap_list *ap = malloc(sizeof(ap_list)) ;
   memcpy(ap->mac_addr_bytes, mac_addr_bytes, ETHER_ADDR_LEN) ;
@@ -1026,9 +1019,8 @@ void push_ap(ap_list *ap)
  */
 void* monitor_aps(void *NULL_value)
 {
-#ifdef DEBUG
-  fprintf(stderr, "Monitor AP thread launched.\n") ;
-#endif // DEBUG
+  if (VERBOSE_WARNING)
+    fprintf(stderr, "Monitor AP thread launched.\n") ;
 
   while (owl_run)
     {
@@ -1079,12 +1071,13 @@ void delete_old_aps()
  */
 void delete_ap(ap_list *ap)
 {
-#ifdef DEBUG
-  assert(ap) ;
-  char mac_str[OWL_ETHER_ADDR_STRLEN] ;
-  owl_mac_bytes_to_string_r(token_aps->mac_addr_bytes, mac_str) ;
-  fprintf(stderr, "Deleting AP « %s »...\n", mac_str) ;
-#endif // DEBUG
+  if (VERBOSE_INFO)
+    {
+      char mac_str[OWL_ETHER_ADDR_STRLEN] ;
+      assert(ap) ;
+      owl_mac_bytes_to_string_r(ap->mac_addr_bytes, mac_str) ;
+      fprintf(stderr, "Deleting AP « %s »...\n", mac_str) ;
+    }
 
   unlink_ap(ap) ;
   free(ap) ;
@@ -1134,9 +1127,8 @@ void order_send(ap_list *ap)
   int sockfd ;
   ssize_t nsent ;
 
-#ifdef DEBUG
-  fprintf(stderr, "Sending an order to %s...\n", ap->ip_addr) ;
-#endif // DEBUG
+  if (VERBOSE_INFO)
+    fprintf(stderr, "Sending an order to %s...\n", ap->ip_addr) ;
 
   sockfd =
     owl_create_udp_trx_socket(ap->ip_addr,
@@ -1272,8 +1264,8 @@ void print_usage()
   printf("Usage:\n"
          "\t%s"
          " [-f config_file]"
-         " [-v]"
-         " [-o output_file]"
+         " [-v[v[v[v]]]]"
+         " -o output_file"
          " [-i positionner_ip]"
          " [-p positioner_port]"
          " [-l listening_port]"
@@ -1293,8 +1285,10 @@ void print_usage()
          "\t-V\t\tShow version information.\n"
          "\t-f config_file\tUse 'config_file' instead of the default"
          " configuration file (%s).\n"
-         "\t-v\t\tBe verbose (you can use this option several times to"
-         " increase the level of verbosity).\n"
+         "\t-v\t\tBe verbose. You can use this option up to 4 times to"
+         " increase the level of verbosity (1 = warnings, 2 = useful"
+         " information, 3 = too much information, 4 = displays the"
+         " detail of each and every received request).\n"
 
          "Output options:\n"
          "\t-o output_file\t\tAggregated requests will be appended to"