By Tim Conneally, Betanews

Popular microblog Twitter has blocked third-party mobile Twitter apps Twidroyd and UberTwitter on Friday, citing unspecified policy violations.

"Every day, we suspend hundreds of applications that are in violation of our policies," the Twitter Help Center blog said Friday. "Generally, these apps are used by a small number of users. We are taking the unusual step of sharing this with you because today's suspension may affect a larger number of users."

Indeed, both of these applications are extremely popular.

Both of these popular Twitter applications are owned by UberMedia, a company which has Twitter clients on all mobile and desktop platforms, and has been regularly acquiring software startups to broaden its presence and build new services and features into its Twitter clients.

Effectively, the company has been building a better Twitter (or at least better Twitter apps.)

Earlier this week, UberMedia announced it received $17.5 million in funding from Accel Ventures, and that investor Jim Breyer would join the company's board of directors. Breyer has been on the boards of Facebook, Dell, Wal-Mart, and Marvel Entertainment.

UberMedia's aggressive acquisition strategy, extremely popular software offerings, and recent Board addition all make it a threat to Twitter's extremely high market value.

Copyright Betanews, Inc. 2010