when it comes to making friends on the site, what i've found is (at least for me) if someone relates to your thread in some way, you just start talking and before you know it you're close friends on here.

for example

poster 1: i'm agoraphobic and hate summer

poster 2: oh yes, me too!. can we talk about it?

poster 1: sure

i think most of the friends i have on here are because of threads that either i or they have started. i hardly ever just message someone out the blue, unless they are either new, or they need extra support with something