Good news: The Mozilla team has fixed the networking issue which required us to force our users to enable third party cookies. As a result, if you are running firefox 3.0.7+ or firefox 3.1, feedly (1.2.208+) now works with or without third party cookies enabled. Thank you to the Mozilla team: Firefox just keeps getting better and better!
Update: OK. It seems that this snake is not 100% dead so we are rolling this change back and will look into this in more detail tomorrow/next week. We will update this thread as soon as we have more information.
Update (Marsh 29th, 2009): It ended up that the firefox team had not fixed the issue in 3.0.7. But we were able to address this issue by allowing users to keep third party cookies off but creating a set of exceptions for feedly.com, google.com, twitter.com. See http://www.flickr.com/photos/65995199@N00/3394972470/ for more information. Sorry it took so long. We are happy to see this issue finally resolved.