Business model: RSSCalendar enabled users to create RSS feeds from Outlook and iCal calendars. Lookout Software, L.L.C. purchased it on eBay in October 2007, carrying it on as a similar service.

Why it failed: If people aren't ready for RSS -- both Forrester and Pew report that only 5-6% of the U.S. population actually use it -- then they're not ready for an RSS calendar.