Twitter Inc. is in advanced talks to buy TweetDeck Inc. for around $50 million. TweetDeck was reported to be in talks to sell to UberMedia for $30 million in cash and stock. UberMedia is reportedly going to use its base of Twitter clients as a way to launch a Twitter-like service. If it owns TweetDeck, then UberMedia has an even strong base for its own Twitter-killer.

TweetDeck has at least 15 employees and contractors, most of whom are located in the U.K., according to its website. Twitter has been recruiting engineers and others in London and plans to open a U.K. office this year, people familiar with the matter said.

TweetDeck has raised several million dollars from well-known Internet-technology investors including Ron Conway’s SV Angel firm, John Borthwick, Bill Tai and others.