Most Influential Virtual Worlds of the '00s

Started in 1999 by Linden Lab, Second Life is still the virtual world front runner in terms of sophistication and virtual reality living. With an economic structure (and money that can be exchanged for real world currency), real estate system, user-owned businesses and more, you can easily lose yourself in the 3-D Second Life world. Second Life is used by a variety of businesses and organizations for meetings and seminars and has infiltrated Hollywood via shows like CSY: NY and The Office. Second Life has been a major player in the rise of mainstream awareness of virtual worlds from 2000-2009. It also holds the record for the "Most Financially Rewarding MMORPG" according to Guinness.

World of Warcraft is a bit different from other virtual worlds on the list. This MMORPG (massively multiplayer online role-playing game) is a video game that users buy and then subscribe to online. One of the most popular MMORPGs, World of Warcraft draws players of all ages, cultures and backgrounds. It holds the Guinness World Record for the Most Popular MMORPG, solidifying its role in turning geeky gamers into today's cool kids.

Club Penguin launched in 2005 and quickly became a popular hang-out for teens and tweens. Unlike Webkinz, Club Penguin is designed for users to interact with each other through games and moderated chat. It's one of the first examples of social networking for younger kids and it's differentiated from Whyville by its emphasis on entertainment over education. Club Penguin became such a big phenomenon that it was purchased by the Walt Disney Company in 2007 for $350 million (another record). Although Disney already managed a MMOG (massively multiplayer online game) in Toon Town, Club Penguin is geared at a slightly older, and more social, crowd.

Runescape is one of the most popular free MMORPGs. An optional subscription service is available, giving users access to additional features. Runescape, which launched in 2001, shows up on this list in part for its popularity, but also for the level of quality it puts forth as a free site. Runescape draws a variety of ages, but it extremely popular with teens. They hold the Guiness World Record for the Most Popular Free MMORPG and also the Most Prolifically Updated MMORPG.

Habbo, or Habbo Hotel, is a virtual world and social networking site. Users can decorate rooms in the hotel, host parties and interact with each other in social groups. Habbo Hotel has an extremely strong international teen user base, which they encourage through partnerships with recording artists and franchises such as the popular Twilight: New Moon movie. Despite the extreme success, one of the biggest marks Habbo left on the virtual world arena this decade was when several users were accused of stealing more than $5000 worth of virtual furniture from another user. The theft brought up questions about the value of virtual belongings and the ability to police international spaces, and helped spur on discussions of Internet law. It holds the record as the "Largest Virtual Community for Teens."