Feedfetcher placing items in my feed that aren't there

Question

I check RSS feeds more often than I should, so I built an application that delays my RSS feeds between midnight and 5 PM, so I don't check them (see http://rssafter5.appspot.com). I take an RSS feed as input and create a custom feed on my domain that doesn't check the source feed until 5PM every day (and hence doesn't update).

However lately Feedfetcher has been placing new items in my (custom) RSS feed before my custom feed actually updates. For example, my custom MarginalRevolution feed currently (4:30PST) does not display any items after midnight on Sunday night, but this morning at 10AM Google Reader displayed a post that went on Marginal Revolution today at 9 AM. In most cases this would be a benefit, but I'm specifically trying not to read the feed until 5PM, so it's destroying my app's functionality.

How can I get Feedfetcher/Google to recognize that my feed is distinct and stop aggregating/replacing my content with the fresher content from the original site? Thanks for the help, Kevin

Answer 1

Either you leak items from your rssafter5 feed, or Google/Feedfetcher are trying to be very clever and anticipating items that haven't even appeared in your feed, based on resemblance to the original feed.

While the latter scenario seems unlikely to me, here's a hack that may well prevent such behavior:

In your rssafter5 app, change the GUID of each post before releasing it. For example, append the string "delayed" to the GUID. If that doesn't work, try modifying other properties as well. For example, change the title by adding an extra space or   somewhere.

Some things to check for in your app to make sure you don't leak:

• Don't rely on timestamps from the feed owners, but determine your own timestamps.
• Are there any corner cases you missed that could leak an item? Google needs to see an item only once and it will not remove it anymore even if it disappeared from the feed 5 minutes later.