Looks like TypePad is a mainstream one: http://techcrunch.com/2009/11/17/typepad-dives-into-micro-blogging-with-an-important-new-feature-free/ http://techcrunch

Looks like TypePad is a mainstream one: http://techcrunch.com/2009/11/17/typepad-dives-into-micro-blogging-with-an-important-new-feature-free/ http://techcrunch.com/2009/11/17/typepad-dives-into-micro-bl... "...TypePad considers the new Micro product be fit in between what people do on Twitter, and what they do on regular blogs"