I've got a website with a tagging system similar to StackOverflow's. And I'm in the process of creating the ability for the user to subscribe to any tag-based search through rss. I think I've just about got it all figured out except for one thing.
Because of this flexibility I'm creating, the potential number of different rss feeds coming from the site could be staggering (thousands and thousands). And I can't input each of those into FeedBurner. But I'd still like to measure the traffic. In particular, I want a number of unique rss views, or unique subscribers. I'm not going to be too picky about it being 100% accurate... but I think uniquely identifying this rss traffic in some way will make the figures more useful.
At the simplest level, I could determine uniqueness based off of the IP address. But if someone is reading an RSS feed through an online feed aggregator, then won't their IP address be obscured? I would then be tracking the IP address of the aggregator, and if many people visited the site through the same aggregator, it might all be the same IP. So what would you suggest?
I posted a comment about PubSubHubbub, but I also think this applies for analytics. With this you'll easily be able to know how many service subscribe to each feed. (note that it's service, not people).
Then, to measure the actual Views, or even susbcriber, it is much harder. One way would be to track different things and extrapolate from there. First, you can of course track the number of "hits" on each feed. Check for the IP and the Useragent as they may give adequate information. Then, you can insert (X)HTML content in your feeds, like images. A 1pxx1px transparent image may be able to give you some valuable insight on how many times a given entry in the feed is seen. Finally (I'm sure there are other ways though!), track the clicks on the links for example. That is extrelemly useful. I'm sure services like Bit.ly can be of help here...