The discussions on e.g. Flickr often consist solely of comments like "Awesome pic! Great colours, looking forward to your next contribution." or "I like your style, please post more!"... To me, this represents the prototype of internet friendliness - not that I would like it to see it here, not that it couldn't be easily faked, but one just cannot deny that it sounds encouraging. There is even no need to talk about ourselves or to say anyting substantial at all, just signal friendliness the most obvious way, it works.

(It's interesting to note how dramatically Flickr differs from Youtube in the commenter culture.)