In 99.99% of projects we've done over the last 4 years, we haven't been using the ConnectionLink module. I then find it a bit unnecessary that the module runs its calculations on every application startup.
Also on the Volvo Worldtrucker.com web server the CPU goes through the roof every time we release something. We talked about this with EPiServer hosting and they say ASP.NET signals a deadlock and ConnectionLink causes the error "ConnectionLink Module failed to handle contact relation event because: Object reference not set to an instance of an object. at EPiServer.Community.ConnectionLink.ConnectionLinkModule.RemoveEdge(Int32 contactContainerUserId, Int32 contactUserId) at EPiServer.Community.ConnectionLink.ConnectionLinkModule.CacheEventHandler.HandlerEvent().".
I think the best help I could get is if someone tells me how to turn the module off.
You can add enabled="false" to the connectionLink element in web.config (or even remove the assembly itself).