David,you are quite right about the forum. I've learnt so much since registering here,being able to upload pics of plants I can't name in my garden has enabled me to gather knowledge about their habits,characteristics etc. I can then take a course of action rather than repeatedly looking at an unknown plant and scratching my head.Of course the same applies to other people uploading pics,an expert member IDs it and we all learn a bit more.
I think there is another factor that makes these forums so friendly and that's a lack of competition. I'm a member on a poetry site where we post our own poems for others to comment on,but at the same time you have to comment on three poems by other people to every one you post. Without openly stating it,there is an element of competition.Who's poem is the best,who gets their poems 'spotlighted' the most etc. Yes I've made some good friends there,but that kind of 'edge' still exists. Here there is none of that and I find it refreshing and comforting