diff --git includes/FeedsSource.inc includes/FeedsSource.inc
index 5c379aa..8ab3b20 100644
--- includes/FeedsSource.inc
+++ includes/FeedsSource.inc
@@ -194,12 +194,18 @@ class FeedsSource extends FeedsConfigurable {
    * Schedule this source.
    */
   public function schedule() {
+    // Check whether any fetcher is overriding the import period.
+    $period = $this->importer->config['import_period'];
+    $fetcher_period = $this->importer->fetcher->importPeriod($this);
+    if (is_numeric($fetcher_period)) {
+      $period = $fetcher_period;
+    }
     $job = array(
       'callback' => 'feeds_source_import',
       'type' => $this->id,
       'id' => $this->feed_nid,
       // Schedule as soon as possible if a batch is active.
-      'period' => $this->batch ? 0 : $this->importer->config['import_period'],
+      'period' => $this->batch ? 0 : $period,
       'periodic' => TRUE,
     );
     if ($job['period'] != FEEDS_SCHEDULE_NEVER) {
diff --git plugins/FeedsFetcher.inc plugins/FeedsFetcher.inc
index d4a63ea..88e767f 100644
--- plugins/FeedsFetcher.inc
+++ plugins/FeedsFetcher.inc
@@ -94,4 +94,17 @@ abstract class FeedsFetcher extends FeedsPlugin {
    *   Source information for unsubscribing.
    */
   public function unsubscribe(FeedsSource $source) {}
+
+  /**
+   * Override import period settings. This can be used to force a certain import
+   * interval.
+   *
+   * @param $source
+   *   A FeedsSource object.
+   *
+   * @return
+   *   A time span in seconds if periodic import should be overridden for given
+   *   $source, NULL otherwise.
+   */
+  public function importPeriod(FeedsSource $source) {}
 }
diff --git plugins/FeedsHTTPFetcher.inc plugins/FeedsHTTPFetcher.inc
index dd61e06..c6189d7 100644
--- plugins/FeedsHTTPFetcher.inc
+++ plugins/FeedsHTTPFetcher.inc
@@ -193,6 +193,15 @@ class FeedsHTTPFetcher extends FeedsFetcher {
   }
 
   /**
+   * Implement FeedsFetcher::importPeriod().
+   */
+  public function importPeriod(FeedsSource $source) {
+    if ($this->subscriber($source->feed_nid)->subscribed()) {
+      return 259200; // Delay for three days if there is a successful subscription.
+    }
+  }
+
+  /**
    * Convenience method for instantiating a subscriber object.
    */
   protected function subscriber($subscriber_id) {