Very true. It's the immediacy of it that struck me this morning.
If I make a post telling you that I met Elvis Presley as an old man and you respond with "Pics or it didn't happen". I can literally post a reply to you within a couple of minutes (If I knew where to go) of me meeting an elderly Elvis Presley. Whereas before I'd have to put some effort into it, and then respond a day later with my finished photoshop creation. The immediacy lends it credibility in the way that traditional photo manipulation didn't.