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March 19, 2004

Feed Analysis: Success vs. NoChange

In the two months we are looking at I didn't post very frequently, 3-4 times per week at most. Hopefully most of the feed reading agents will use the "changed-since" when requesting the feed, and rely on the HTTP processing return a 304 if the feed hasn't changed since the last successful request. When we analyze the data we see that indeed over 85% of the requests receive a NoChange response.

More interesting of course is to look at the relationship between polling interval and the chance that you will receive a Success (200) or NoChange (304) response. The graph below shows the percentage of the requests that received a 'NoChange' in response, as a function of the time between this request and the previous request by the same user. It ranges from about 90% change for the aggregators configured with very short to about 20% for those that poll once per week.

Keep in mind that this data is very much dependent on the update rate of the source, which does not generalize to other weblogs.

Posted by Werner Vogels at March 19, 2004 11:51 AM