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YouTube has come to define the era of online video, so let's take a look at its most popular videos of all time. Our latest update has Justin Bieber still at number 1 with Baby, which was the first video to earn a half a billion views! Currently, Bieber and Eminem between them make almost half of the top 10. Also of note is a music video by Jennifer Lopez called On The Floor ft. Pitbull, which has risen to number 2 with almost 500 million views in only 10 months.

We first did this list in August 2007, at which point Evolution of Dance by comedian Judson Laipply was number 1 with nearly 56 million views (it's now outside the top 10). The next update was September 2008, when Avril Lavigne's Girlfriend pop music video was number 1 with 103 million views. In January 2010, Charlie bit my finger - again ! was number 1, with 148 million views. By the beginning of January 2011, Justin Bieber was at number 1 with over 400 million views for Baby.

Here is the top 10, as of February 2012:

Music videos became famous in the early 80's on MTV. Nowadays, music videos are more likely to be viewed on the Web. Seven of the top ten YouTube videos of all time are music videos - from the likes of Lady Gaga, Shakira and Justin Bieber. The increasing popularity of music videos online led the AP to proclaim that "watching music videos has become [a] central aspect of Internet usage."

AP points to an experimental Web video by Arcade Fire, created using advanced browser technology HTML5, as evidence that the music industry is adapting to videos on the Web. In related news, according to online analytics firm comScore, MTV is now the number 1 music destination on the Web. So it too is evolving fast.

As we pass the 80 day mark in the greatest underwater oil spill of all time, here's a chance to pause and reflect on the most-viewed YouTube videos about the spill. Our selection doesn't include popular videos that claim environmentalists caused the spill to further their own agenda, nor does it include any official videos from the company whose leadership is the true cause of this disaster.

What is included are several parodies of how BP is handling the situation, as well as a newly released video of whales and dolphins dying in the slick. Many of these videos will soon be out of date as hurricanes and other unexpected events dramatically change the overall story of what BP has done to all the life that calls the Gulf of Mexico home. If you know of any important YouTube oil spill videos that were left out of our collection please posts a link to it in the comments below. If you'd like to learn more about the latest in Web technology as it relates to the oil spill please view our coverage here.

A world where we download objects off the Web the same way we currently download our data? If this futuristic notion is one day going to come true, it's thanks to 3D printing developers like FormZ, ProtoPulsion, Z Corp, Print2 3D, and Thing Labs. Our selection of the top videos mostly come from these companies.

The number one video in this collection, however, is more ideal than real. The Star Trek Replicator according to Wikipedia "...can create any inanimate matter, as long as the desired molecular structure is on file, but it cannot create antimatter, dilithium, latinum, or a living organism of any kind. In theory it seems to work similar to a universal assembler." In the real world, today's developers have countless innovations they must achieve before 3D printers can come anywhere near Star Trek's replicator. But once it does become possible, what's the first object you'd most want to download off the Web?

From guest panels about the challenges women face in the technology sector, to interviews about the challenges they face in a male dominated work environment, this collection of videos shines a light on women in tech.

The list includes Caterina Fake explaining how she became co-founder of Hunch and Flickr, as well as Dianne Marsh speaking about the under representation of women in computer sciences. Also included is a video about a data center a women built, and an interview with a college student majoring in computer science. Best of all is the top video She's Geeky, which is about an all-female unconference facilitated by Kaliya Hamlin. (ReadWriteWeb's Mobile Summit on May 7 is going to be facilitated by Hamlin.)