Twitter is direct. I can work out lunch arrangements or a meeting about a business opportunity very quickly, with multiple people, from anywhere, as long as I have at least SMS access. This gets at the heart of what Twitter is... Twitter is another level of indirection (for you C programmers), or another layer (for you networking people), for connecting people, and that, combined with its simplicity and ease of operation, makes it very powerful. It's a big lever and a light touch is all you need