Keeping up with multiple RSS feeds can be tough. Yeah it's really simple, but that syndication bit is what always gets me. Google has introduced a fresh way to analyze both when blogs you subscribe to are posting and when (and if) you're actually reading them.
The data is represented with simple colored bars, with the blue being post time and the red as the time you typically get your reading done. You can dig down even deeper and split up the monthly data by the time of day, or day of the week. The results can be startling.
The system does not currently work with groupings of blogs, but on any single feed, clicking the "show details" link gives you a small drop-down with publishing verses readership information. In the future I'd love to see the option to view your reading habits with groups of blogs so I could reconsider which clusters deserved more attention. An alternate way to do this is to look for blogs you're not reading, or that have dried up using trends.