In 2000, the only ones tweeting were the birds. In the age of Twitter, tweeting has a new meaning -- to post messages on Twitter.

The Twitter phenomenon was one of many cyberculture developments that shaped life in the first decade of the 21st century. Social networking and downloading or streaming music made the Web a hub for socializing and for entertainment.

Personal technology found its way to the world stage. Cell phone cameras captured history, such as the Iranian election protests. Skillful use of social networking sites and the Internet played their first major role in the election of a U.S. president.

Here, in no particular order, are the top 10 most influential developments of the decade:

In 2000, we were still fettered to our computers. As the decade advanced, new devices allowed us to stay connected to the Web from almost anywhere.

The growth of wireless Internet connections untethered laptops, personal computers and portable music players. The technology existed in the 20th century, but the new decade saw the rise of Wi-Fi hot spots in public areas, air cards that connected computers to the Web from anywhere, and access throughout the home with wireless routers.

The way people listened to and bought music changed forever. The Apple iPod portable media player was introduced in 2001. People were able to load the tiny players with their favorite music and listen to their own personally created playlists anywhere.

As the decade advanced, Apple added bells and whistles to the iPod, including the ability to watch and record videos.

The iPod Touch, introduced in 2007 -- an iPhone minus the phone service -- enabled people to connect to the Internet wirelessly to download music and listen to many Internet radio stations.

The popular but not-so-legal music download site Napster was shut down in 2001, but the barn door had opened forever.

In 2003, Apple opened the iTunes store, allowing people to legally download songs for 99 cents from the Web. Five years later, it was the largest music retailer in the United States. The store's offerings expanded beyond music, offering movies, TV show episodes, podcasts and games.

Amazon and Walmart are the other major players in the entertainment download field, and the concept of downloading a song instead of buying a CD moved out of the college dormitory and into the mainstream.

Smartphones took the ubiquitous cell phone to a new level.

BlackBerry launched in '99 as a two-way pager. In 2002, the BlackBerry smartphone debuted. It combined a mobile phone with e-mail, text messaging and Web browsing, along with address book and calendar, making it an indispensable assistant to business people.

The decade also saw the coining of a new word -- CrackBerry -- referring to the addictive behavior of some BlackBerry users. CrackBerry was named new word of the year by Webster's New World College Dictionary in '06.

The advent of the iPhone in 2007 brought all that BlackBerry did to an Apple device, along with crisp, colorful graphics and an easy-to-use touch screen.

The introduction of downloadable applications, or "apps," made smartphones the Swiss Army knife of tech devices -- capable of balancing checkbooks and tracking calories, serving as an e-reader for e-books and newspapers, or as a portable gaming device with visually dazzling displays, and much more.

It was the decade where everyone became a star, if he or she wanted to. YouTube made its debut in 2005, and the user-generated video site turned into a worldwide phenomenon. People uploaded their own video creations -- hamsters on treadmills, people singing in their bedrooms -- to share with others. Some videos went viral and reached a global audience.

YouTube is now a kind of pop culture archive where you can find everything from on-the-scene news reports, band performances, and movie trailers and excerpts.

The availability of low-cost video camcorders, portable camcorders and cell phones with video capability also helped to fuel the online video revolution.

Once user-generated videos started attracting large numbers of viewers, the medium was adopted by professional video and filmmakers, who created original Web-only series. Now many TV series are available for viewing online.

MySpace launched in 2003. It was modeled after Friendster, which debuted the year before. Users -- especially younger people -- embraced it as a way to post their profiles online, connect with friends and meet new ones. It quickly became a way to promote bands and entertainers.

In 2004, Facebook was created initially as an online social network for Harvard students. It extended to other Ivy league schools, then all schools and eventually to anyone who wanted to join.

It created a new word -- or rather repurposed an old one. "Friend" became a verb, as in "to friend" someone on a social networking site. It was inevitably followed by another new verb -- "to unfriend." There are now 350 million people on Facebook worldwide.

You should be able to say everything you need to say about Twitter in 140 characters or less: That's the maximum space allowed for a Twitter post. This personal messaging and microblogging site has evolved into a major cultural player. The early details of breaking news stories appear on Twitter. Movie celebrities who used to rely on publicity people can now issue their own tweets to fans.

It has become a quick way for companies to spread their message and to monitor what people are saying about their products. Twitter also played a key role in alerting protestors about the movement of law enforcement during the recent G-20 summit in Pittsburgh.

In these rich computer-simulated environments, participants adopt an avatar and interact with others. Second Life launched in June 2003, and there are numerous others, including Worlds, Cybertown and the kid-friendly Disney's Toontown. Although virtual worlds existed before in online role-playing games, the improvement in graphic displays and simulated 3-D environments made it an engaging new way to spend lots of time online.

The Microsoft Xbox in 2001, Sony PlayStationPortable in '04 and the Nintendo Wii in '05 made video games even more popular than before, with some game titles surpassing DVDs in sales.

Instead of watching bands, people became them, playing popular games such as "Guitar Hero" and "Rock Band." Gaming grew from a pastime for kids and young adults to one enjoyed by all ages.

Blogs, or Web logs, had been around in various forms -- online journals, personal Web sites -- for years. But this was the decade when bloggers found their voice. It seemed like almost everybody blogs, but a few rose to prominence and real influence, such as news and opinion site The Huffington Post, celebrity gossip sources like Perez Hilton and TMZ, and geeky hangouts like Boing Boing and Techcrunch.

Doug Oster writes a blog, "Growing With Doug," exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.