A common issue with Community Server 2007 was frequently required logins. This was always resolved by adding a MachineKey to the web.config. I add a MachineKey to each of my CS sites as one of my first setup tasks. In working with CS2008 I quickly realized that this was something I’ll continue to do, as I found myself having to re-login unnecessarily. It takes 30 seconds to generate a key at ASP.NET Resources and add it to the web.config, so it’s not a burden or anything. Fine nuglet material though.