Vator has a growing group of very cool startup companies using the "company updates" feature (Kosmix has over 1,000 followers, Digger over 400, etc.).
It's a Twitter-like micro-blogging feature (in fact, you can configure it to automatically update your Twitter account).
What's cool about the Vator service is that Vator will often recommend companies to follow - so if you're active with your updates you will find that your follower base grows quickly. In addition, the quality of the community and followers is extremely high. So you'll find you're gaining awareness with VCs, angel investors, investment bankers, strategics, partners and other entrepreneurs.
Vator then packages up your updates and sends them out in daily email blasts. So your name and brand is (unobstrusivly) staying in front of key influencers in the industry.
I have more followers on Vator now than Twitter - and the quality of the followers isn't even comparable.
You can see my profile here. Click to follow STRATEGYfx/me from that site.
To set up your company, and learn what others have to say about Vator, visit this summary page.
The link URL for the summary page is: http://vator.tv/engage
I'm pretty sure there will be a time when it will be a prerequisite for a startup to have an active profile and following on Vator.
Good stuff.