When TweetDeck landed in the Chrome Web Store, it seemed like an indication that it might eventually evolve into a pure HTML5 Web app. Now it looks as though that's exactly what's going to happen, with TweetDeck announcing that a new, not-just-for-Chrome Web client is ready for beta testing.

It's a natural progression for TweetDeck, especially since its originally Adobe Air app is practically all Web code. TweetDeck Web will sport a feature set which is nearly identical to the Chrome app, with the notable exception of Twitter streaming.

Initially, TweetDeck is targeting Firefox 4 and 3.6, Google Chrome, and Safari. Opera and Internet Explorer 9 won't be invited to the dance until a bit later on.

If you'd like to get in on the TweetDeck Web beta, head on over and register -- or sign up using your existing TweetDeck account.

It might only be a couple of years old and its extension interface might not be quite as powerful as Firefox's, but in terms of developers, big-name publishers, and sheer numbers, Chrome already has a very healthy ecosystem of add-ons.

When you factor in Chrome's exclusive selection of Web apps, it's even possible to say that Chrome has a wider variety of extensions -- or at least until Mozilla launches its Open Web Apps later in the year.

Still, as always, the problem with add-ons is finding the right ones. You have thousands of add-ons to , and only a handful that are actually worth using. First-time users haven't got a snowball's chance -- unless they read this list of must-have extensions!

But this list of extensions is for converts, too. With massive defections from Internet Explorer and Firefox, Chrome has grown from just a few million users in 2009 to over 120 million at the start of 2011. Firefox users will be especially pleased to find almost every add-on has a comparable extension -- and IE users... well, they'll just be glad to have any extensions at all.

Whether you are looking for helpers or shortcuts, or full-blown Web apps, you will be pleasantly surprised with the variety and power of Chrome's extensions.

Google publicly unveiled the a week ago. Looking at the in the U.S. by weekly install numbers, it looks like TweetDeck has fast risen to the most prominent spot on the list, as by the startup’s founder Iain Dodsworth earlier today.

With about at the time of writing, TweetDeck thus beats , whose app has seen approximately 87,700 weekly installs to date, roughly seven days in.

So where are the Google services? Right behind the TweetDeck and the NY Times, it appears.

The list of top 10 most popular apps on the Chrome Web Store includes Google Calendar, Google Books, Google Docs, Google Reader, Gmail, Google Maps and YouTube.

Granted, most of Google’s ‘apps’ are mere links to the respective Web-based services, whereas ‘ChromeDeck’ is an actual app, but still.

rounds out the list of the ten most popular apps on the store as the third non-Google service to make the list after TweetDeck and NY Times, with about 35,000 weekly installs (almost a third of TweetDeck’s install numbers).

Obviously, it’s far too soon to draw any conclusions, but it’s certainly a testament to TweetDeck’s huge popularity to see it leading the most popular Chrome apps list, considering the company is primarily regarded as a desktop and mobile client software developer.

For your information, rivals HootSuite (16,000 weekly installs), eBuddy Web Messenger (13,9200 weekly installs) and Seesmic (5,442 weekly installs) are trailing far behind.

TweetDeck, the AIR-based desktop and smartphone twitter power app has finally joined its biggest competitor, Seesmic, on the Web. The for Google's fledgling Chrome Web Store brings the best of what people loved about the desktop AIR-app to the Web, in what Iain Dodsworth, CEO of TweetDeck calls: "definitely our best version of a desktop TweetDeck so far." The Chrome app supports TweetDeck accounts for syncing of read tweets, filters and search columns, and has support for almost everything social. Twitter, Facebook, FourSquare, and even Google Buzz, are present and accounted for, with Gmail support on the way.

TweetDeck for Chrome is aiming to be faster and lighter than its AIR-based cousin, which is good news for anyone who's wanted to use TweetDeck on the desktop but has been put off by the relatively large footprint the AIR app takes. It's also currently silent, but TweetDeck is looking to implement a new 'social soundscape' across all its TweetDeck products in an effort to unify the notification system -- great for knowing what's happened without having to look at your screen.

The TweetDeck Chrome app can be and installed directly into your up-to-date Chrome browser.