Microblogging site Twitter is said to have acquired popular Twitter application TweetDeck by paying more than $40 million.

TweetDeck, founded by Iain Dodsworth, is a desktop application for Twitter, Facebook, LinkedIn Google Buzz, Foursquare, and MySpace. Like other Twitter applications it interfaces with the Twitter API to allow users to send and receive tweets and view profiles.

The deal makes complete sense as Twitter as a way to read and write tweets is a no-frills platform that loses many people once they get some experience and start to explore alternatives. A recent report from Sysomos shows that 42 percent of all tweets are made using non-official Twitter services and applications, which included TweetDeck.

More enthusiastic and power users are using non-official services such as TweetDeck, UberSocial and Seesmic as many of these applications have many more features than Twitter.com despite recent improvements, Sysomos said in a blog post.

TweetDeck is one of the most popular third-party services because it is feature-rich and user-friendly. Unlike Twitter, TweetDeck has diligently worked on improving, including the ability to post to multiple platforms in the same desktop window -- a feature Twitter itself doesn't offer.

No wonder, TweetDeck is the most popular Twitter application with a 19 percent market share as of June 2009, following only the official Twitter.com website with 45.70 percent share for posting new status updates. Other popular Twitter applications include UberSocial and Echofone, which are owned by Bill Gross' UberMedia

Though neither party have confirmed a deal, CNN reported that papers finalizing the deal were signed on Monday.

TweetDeck has been in the midst of takeover talks for sometime. Recently, twitter apps maker Ubermedia was reportedly in talks to buy TweetDeck, but the deal didn't take off. In April, the Wall Street Journal reported that Twitter might buy TweetDeck.

The reported acquisition is in line with Twitter's strategy, which either downplays competing apps or buys them. In 2010, Twitter bought Tweetie and made it as Twitter for iPhone and in 2008, it acquired the Summize search engine and turned it into Twitter Search.

Moreover, the deal comes at a time when Twitter is being tough with third party developers as it wants to take back its ecosystem and provide a uniform experience to the users.

In February, Twitter had suspended two of UberMedia's apps - UberTwitter and twitroyd -citing that they have violated Twitter's policies.

We want to empower our ecosystem partners to build valuable businesses around the information flowing through Twitter. At the same time, we aim to strike a balance between encouraging interesting development and protecting both Twitter's and users' rights. So, we've come up with a set of Developer Rules of the Road (Rules) that describe the policies and philosophy around what type of innovation is permitted with the content and information shared on Twitter, Twitter said in a blog post.

The Rules will evolve along with our ecosystem as developers continue to innovate and find new, creative ways to use the Twitter API, the blog post added.

Consequently, developers who felt they had helped Twitter grow were reportedly not too happy about the memo.

On the other hand, Ubermedia, which has made several apps for the Twitter platform, is said to be planning a competitor to the micro blogging website and had planned to buy TweetDeck. Media reports suggest that the Ubermedia's talks with TweetDeck made Twitter more aggressive towards the deal.

Now, the million-dollar question for TweetDeck users is how the software will be used as part of the Twitter empire.