I keep seeing answers like this pop up in the Review queue:
There is another source for VoIP. You should have a look at https://code.google.com/p/idoubs/
Seems like a clear case of Not an Answer, and it's been flagged as such. The problem is that the question sucks even more:
I am developing application which required SIP (VOIP) calling in iOS.Please suggest me about SIP server and how to implement it in iOS.
It's a terrible question, and the terribleness of the answer is a direct result of that. In context, it's hard to call this a non-answer; it does address the question, and is as close to an answer as this was ever going to get. Obviously the question needs to be closed, but what should be done with the answers it spawned? Is the Not an Answer flag valid or not?