Let me go through what has been done, and what has not.
A noticeable change has been the ability to items "Mark as Important", or in the Google Reader lingo, "Mark as Starred". Liferea will synchronize this flag to, and from, Google Reader.
Another cool feature that has been added is an efficient feed updater (Let's call this fast-update). So here's how it works: Every 10 minutes, Liferea will make a request to Google Reader asking for a list of modified feeds. The response is very small, and hence this does not affect your bandwidth. But from this small request, we can determine a list of feeds that have been updated, and so we can download exactly these feeds. This means that when a new post is available, you will get the update within 10 minutes! Every 24hrs, a full-update is done to complete the synchronization, because there are some situations where fast-update can miss out subscriptions.
What does not work
Comments do not work (as I have pointed out in the past, this is something I cannot fix). I decided not to implement Labels as Folders, simply because some users (who might have been more generous at tagging their subscriptions!) would not like it.
Synchronization with other Web-based aggregators
True --- I wanted to work on this. However, I couldn't get myself motivated enough, because I didn't think I will be using it. :-) I would have had to learn the intricacies of the new API. (Btw, the Google Reader API is *nasty*!) And plus, since I won't be using it, I won't be able to maintain it properly. (oh, excuses!) If you need help implementing synchronization for another web-based aggregator, I will be ready to help. As long as they provide a clean API, it should not be too hard.
That's all folks!
Although SoC is almost over, I will continue developing and maintaining the Google Reader code in Liferea. So you are most welcome to give me suggestions at any time.