Well, I can't speak for everyone, but I usually go check out the journal of anyone who friends me. (Once I notice, which could take a while.) If it's a real person and not a troll or something (you'd be surprised how much free time some people seem to have), I usually friend right back if we have something in common.

Hi. :o)

Some people have "friending" policies on their user info pages. I'm not that formal (or organized) a person.

Oh, and lj's spellchecker is a thing of beauty, isn't it? I love how it doesn't recognize stuff like the "doesn" part of "doesn't."