Even as a marketer, and someone who uses social media in marketing efforts I am not in favor of mass DMing. If people are actively interested in what I have to say they will follow me (or my company) - if I have an event, webinar, product release, whatever to promote I update my status and it is in my time line - as soon as we marketers start pushing things down peoples throats we could possibly kill a great tool like twitter.
just my .02 @mrboilermaker
