Gmail The main reason for Buzz's fast growth is also its Achilles' heel - it's seamlessly built into Gmail. This is great for Gmail users, but for everyone else? Convincing people to sign up to a new website is hard enough, but to get them to sign up to a new email account and all the associated Google stuff that goes with it, well, that might be harder. For many people it's going to be a deal breaker. They already have their email sorted out. No need for Gmail.

Apps The main players in the game, Twitter and Facebook, both have rich, stable APIs that allow programmers to build applications based upon their services. There's a whole array of apps for computers, mobile phones and games consoles. Google Buzz doesn't have this ecosystem yet, but a full API is coming very, very soon.

Need I have an extensive network on Twitter and public and private Facebook profiles. Do I really need Buzz as well? I don't think so. Not yet anyway..