I'm a late arrival to the language and have almost interacted with it exclusively through StackOverflow and Github. I've been astonished at not just how friendly people are, but how quickly I can get a helpful response to even what I feel are pretty esoteric (and dumb) questions...again, one of the problems of coming into R is that, because of the relatively small community, there aren't as many references or easily Googlable answers compared to Python...but getting answers to questions if you ask them is very easy, and I think that's a credit to the community.

On the other hand, there seem to be a lot of useful libraries that haven't been ported over to Github or are otherwise easily accessible beyond CRAN...Many of them probably don't get as much exposure as they would if they were more easily discoverable...and I honestly don't even know where, in those cases, to start the bug reporting/patching process. That's obviously the fault of my being spoiled by Github...but that's kind of the point, there's a bit more friction in contributing to R than you might find in Python/Ruby/etc.