We have recently been working on very significant changes to our infrastructure. On Sunday we released Patch 0.8b which enabled some social features (e.g. chat, leaderboards) which rely on this new infrastructure, however we subsequently pulled the update after issues were uncovered. Since then, we have been identifying and resolving a number of these problems.
Naturally we wish to avoid a similar situation occuring in future, and so we are making an updated version of Patch 0.8b available on an opt-in basis. If you are interested in helping us test this update, please see the following post for instructions on how to access it. This testing currently only involves a Windows client available through Steam.
If you do opt-into this testing, please report any issues you encounter here in this thread. Thank you to everyone who chooses to help us with this testing, we very much appreciate it.