Piece here on Mashable about the use of Twitter for marketing. Nothing remarkable in that, there's lots of marketing taking place on Twitter, a little by companies promoting themselves or looking for leads or insight, but far more by Twitterers selling themselves in various different ways.
What I did like though was the phrase: Is Twitter Vulnerable to Marketer Attack - it puts marketing right up there with virus writers and phishing gangs.
Barbed comments like this are a useful prompt to remember that marketing should always add value, giving the customer information that is helpful to them. In the age of conversational marketing, this is more true than ever.