I am a Yate user and I can tell their mailing list suffer the same problem. My solution? I often ask for help but, as a personal policy, I always write an article or add to an existing one on the project wiki explaining and documenting what people explained to me. This creates a triple value: 

1.   I have stuff explained 
   
2.   other people can find this explanation just googling around 
   
3.   I don't have to mantain a separate documentation for myself, I just keep referring to (google and) the project wiki (when I don't exactly remember things I sometimes end reading the wiki and saying "oh, I wrote this!")
   

I suggest, in the end, a kind of "ok I'll give you help but you write this stuff in a piece of documentation" policy. I got the name, too: "The Wiki Tax" ;)