With over 26,000 followers, West Hollywood’s Roxy Theatre is the most popular club on Twitter . Just short of half a decade earlier, however, the fortunes of the historic venue and many of its neighbors on LA’s infamous Sunset Strip were waning and in need of serious attitude adjustment. We had a chance to talk with Nic Adler, owner of The Roxy and the man behind the club’s transformation from “castle on the hill” to social media juggernaut, about how Twitter and other tools helped not only reverse the fortunes of businesses on the Strip, but build up a stronger, more vibrant local community

Forbes has released its annual list of the world’s billionaires and when it comes to technology, the list includes many of the same faces we see year after year .

Last night at its Campfire One event, Google officially launched the Google Apps Marketplace . The Google Apps Marketplace offers third-party developers and services a way to integrate directly with the Google Apps platform and sell that integration at whatever price point they choose. This is a huge win for the cloud because it finally allows other cloud services to tap into some of Google’s APIs for things like Gmail and Google Docs at a much deeper level, which can benefit their own customers, as well as offering additional value to Google Apps itself

This post is part of Mashable’s Spark of Genius series, which highlights a unique feature of startups. If you would like to have your startup considered for inclusion, please see the details here . The series is made possible by Microsoft BizSpark.

Last month, we reported that Facebook was transitioning from application notifications to e-mail notices . Today, the Facebook Developer blog has added further information about this new method and announced that as of March 1, 2010, app notifications will be discontinued.

If you’re one of the many searching for footage of SeaWorld trainer Dawn Brancheau (who was killed by Tilikum the whale during a show), be warned: You could be vulnerable to viral attack, or, at the very least, a Rickroll . Ever since the tragic incident at SeaWorld on Thursday, the top Google search term has invariably been “killer whale kills trainer footage” — meaning that many Internet surfers have been keen on getting a morbid glimpse of Brancheau’s death

Somewhat quietly, myYearbook remains one of the most popular social networking sites, with 20 million members and a place in the top 30 most trafficked websites in the US.

Individual stats like Facebook passing the 400 million user mark, Twitter hitting 50 million tweets per day, and YouTube viewers watching 1 billion videos per day are impressive on their own, but what if we looked at Internet-related stats collectively? Jesse Thomas did just that in his video State of the Internet . The video — created and animated by Thomas with data from multiple sources — highlights some remarkable figures and visually depicts the Internet as we know it today

Twitter phishing attacks caught some users off-guard this week, and some expressed surprise that such attacks remain effective. Perhaps we shouldn’t be surprised: Not only do we tend to trust direct messages sent by friends, but the rise of short URLs and a trend towards federated login systems ( Facebook Connect et al) may further confuse new users