Why yes, there is an RSS reader built into the iPhone. To access RSS feeds on the iPhone, all you need to do is enter the RSS feed URL into the Safari address bar. The feed is seemingly fetched through http://reader.mac.com. Radical, huh?
In fact, one of my readers clicked through my RSS feed and I was able to capture the referrer and user agent.
Http Code: 200 Date: Jul 15 17:21:13 Http Version: HTTP/1.1 Size in Bytes: 9887
Agent: Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/1A543a Safari/419.3