Why did dlvr.it post an old item from my feed?

dlvr.it will not post an item unless we find it in your feed at the time we retrieve the feed and make the post.

There are a few known issues with blog systems and third party feed hosting services that can cause dlvr.it to post old items from your blog/feed:

1. Once an item leaves your feed, dlvr.it retains the history of that item for 30 days, and then it is removed.
   
   If the item is re-added to the feed before the 30 day expiration occurs, we will continue to recognize it as having been seen before, and the 30 day counter will reset.
   
   If the item is re-added to the feed after the 30 day expiration occurs, dlvr.it will see this as if it were a brand-new item being added to the feed for the first time and it will be re-posted based on your existing rulesets for number of items, filters, etc.
   
   
2. If you remove items from your blog those items are also removed from your feed. When this happens older item can "bubble up" into your feed. If dlvr.it hasn't seen these old items before, then dlvr.it may post them to your social networks.
   
   If you edit an old item from your blog, some blogging systems will move that revised old item into your feed based on its updated timestamp. If you change the date on an item currently in the feed so that it is older than the other items, this can cause the item to disappear from the feed and cause a newer item to appear in its place, similar to #2.  This can cause dlvr.it to unexpectedly post an old item.
   
   
3. Some blogging systems can 'hiccup' and re-post old items in your feed. This most typically happens when the user makes significant changes to their blog configuration / settings. In this case, old items are often given new GUIDs and are seen by dlvr.it as new items. However, there are cases where the blogging system has spontaneously re-posted old items to the feed. This can also happen when you transition to a secured domain and new permalinks are issued to your pages.
   
   
4. Some third party feed providers (most notoriously Delicious) spontaneously hiccup and repost old items to the feed. This typically is a brief hiccup and by the time you check the feed, the old items have dropped off the end of the feed and only the newest items are then present in the feed.
   
   
5. In some systems, new comments may trigger a new post. In these cases, you can implement a filter in dlvr.it's system if the word "comment" is included in the link. For more information, check out our documentation regarding filters.