Twitter’s exponential growth has attracted global attention, from food trucks to blue-chip brands, and one important component of their success was opening up to third-party developers and scaling out at a time when most companies would be scaling up. This decision turned out to be a great move, and now two companies have emerged as must-have applications: Brizzly and ReFollow

Brizzly, built by Jason Shellen and other Google Reader team members, provides a better user interface than Twitter. You can manage multiple Twitter accounts through one interface and easily toggle between them, save searches, and add profiles to groups. At TrendSlate, we communicate with various venture-capital firms & entrepreneurs across Southern California, and Brizzly is essential to the work we do.

ReFollow by Originate Labs, which is partially based in Los Angeles, has many features that enable users to build a larger following. It also includes features that allow users to sort followers by relationship and batch follow or unfollow others. The easy to use interface combined with powerful rules-based following or unfollowing features make this an essential tool for marketers and individuals that want to build up their follow count.

Both of these sites greatly enhance the Twitter experience and I would imagine that the increased usage may lead to them becoming acquisition targets for Twitter, especially Twitter moves closer to its monetization goals.