Not much happens on Writers.net anymore, but recently a dude livened things up with an annoying introduction. Basically in the "New Member Introductions" forum he posted a commercial for his book. The headline for this commercial proclaimed himself "Canada's #1 Master of Suspense."
The thing of it is, maybe "introducing yourself" with a commercial isn't against any Terms of Service, but it's just a dumb way to go about it. It's like walking into a room and shouting "BUY MY BOOK!" It's a huge turn-off. I mean come on, who likes getting cold calls or having some salesperson showing up on their doorstep? Hardly anyone, so it's more likely to backfire on you than generate any sales.
Then there's declaring yourself the "#1 Master of Suspense" when you vanity published your book and it's ranked over 1 million on Amazon. How corny is that? Of course the dude says someone else called him that, but you're the one using it as the header of your post and in the description for your book, so you're not backing away from it.
Additionally when someone critiques your story, it's not a good idea to start raving about copyright infringement. If you put a sample of your book out on the web, you can't really bitch if someone finds it and critiques it.
Anyway, the point here is when you're introducing yourself to a writing group, online or in person, don't be a selfish dick. Act like you actually give a shit about the group, not just moving a few copies of your bullshit vanity published book.