It’s no secret that many businesses, from large companies to small start-ups, are present in the social mediasphere by way of Twitter. But, I’ve never quite been able to grasp Twitter’s business landscape in terms of what companies are there and how they add up—until yesterday.

I happened upon a new service called twibs– a business directory for brands, companies and organizations on twitter. As of today, twibs has over 4,000 listings. I can view each of the listed company’s most recent tweets and search the directory by way of tags, number of followers or alphabetical listing.

Pretty sweet. To be honest, it won’t be a service I will often frequent. But knowing that it exists will be more than a starting point in the event I want to find a twittering business. With more and more companies grasping Twitter’s potential value, it’s great to have this quick reference, however with the caveat that it will only be as useful as it is up-to-date and relevant.

On a related note: Check out this great post detailing 40 of the best twitter brands and the people behind them.