Oh, sure. The question is how best to get those readers.
I'm one of those who do not respond well to blatant prodding for mindless promotion. I've some bookmarklets for posting things on friendfeed and HN, and use them when a site is interesting.
Maybe those buttons work well with others. But will they create the kind of audience you want? Does that even matter when you're just trying to get some initial attention?
Do they do so for me. If I think something is interesting or valuable, I'll tell people, and do it in my own way.
I don't see how these buttons help me or add value to the content of a site. I'd rather readers be encouraged to participate in a discussion.