Just an FYI — we’re in the process of investigating a nasty tasting bug that’s sitting somewhere between Flock and Delicious.
Apparently Favorites are disappearing (*gasp!*) without a clear reason. Lloyd thinks that it might be something on Delicious’ end, but we’re still looking into it. Rest assured, no existing data is being lost — however, creating new favorites is definitely flaky (possibly because of interactions on the server side).
Keep an eye on Bug #2919 for details. To report any issues you run into, drop a bug report to feedback (at) flock dot com. We’ve got our best people on this, so I’ll let you know the outcome as soon as I get word.