By Kelly Green Morrison and Karen Whitehouse, Download.com When CNET Download.com opened its doors in 1996, it was home to 3,000 small shareware and freeware applications. Online software distribution was still in its infancy. What a difference a near-decade makes! Since 1996, we've watched the rise of instant messaging, digital audio and the MP3 format, file sharing, spyware and antispyware, and the open-source movement, just to name a few. And we've watched as online software distribution has gone from pipe dream to reality. These 10 applications best represent the top trends in downloading over the past decade. #1 ICQ Today instant messengers are ubiquitous, but when ICQ ("I Seek You") was first released in 1997, it was truly the first of its kind. Though competitors such as Yahoo Instant Messenger and AIM have since encroached on ICQ's territory, this chat client remains enormously popular with international users, and it has remained one of Download.com's most popular applications since its launch. #2 WINAMP Arriving fast on the heels of the emerging MP3 digital format, Nullsoft's Winamp was one of the darlings of the burgeoning digital audio scene in the late '90s. This free audio player quickly gained popularity, becoming one of the most popular files on Download.com, and Nullsoft was eventually acquired by AOL in 1999. #3 NAPSTER Who doesn't remember this controversial file-sharing kingpin? Developed by Northeastern University student Shawn Fanning, Napster was a groundbreaking application that enabled users to share MP3s painlessly for the first time through a peer-to-peer network. Napster has since been sued, shuttered, and reborn as a subscription music service, but its legacy remains. #4 FIREFOX Developed by the open-source Mozilla project in 2003, Firefox was the first browser to show the promise of breaking Microsoft's stranglehold on the browser market. Lightweight, secure, and packed with useful features, Firefox exemplifies the promise of the strengthening open-source movement. #5 WINZIP When CNET Download.com launched in 1996, WinZip was among the first programs in our library, and in the past nine years, it has remained near the top of our Most Popular list. The reason is simple: For many years, WinZip was an essential utility. You couldn't download or send large files without it. Even the fact that Windows XP now has built-in ZIP support hasn't diminished its popularity. The keys to WinZip's success are its simplicity and its singularity of purpose: it does one thing--compressing and decompressing files--and it does it very well. #6 ITUNES Apple's music player and organizer makes our top 10 list for the sheer beauty of its product design. iTunes is not only a full-featured media player and library in its own right, it's also the gateway for Apple's iPod and popular music store, creating an elegant and simple interface for buying and organizing music. If only all software were this easy to use. #7 AD-AWARE Almost as soon as there was software to download, there was adware coming along for the ride. Lavasoft did its part to hold the line with Ad-aware, a spyware scanner and remover. Its simple interface and excellent results have gained the program acclaim over the past five years, including a recent monopoly on the No. 1 slot in Download.com's Most Popular list. We wouldn't download files without it, and apparently, neither would most of you. #8 SKYPE If Internet signals can travel over a phone line, then voice calls can travel over the Internet, right? With a Voice-over-IP (VOIP) program such as Skype, they certainly can. The prospect of making free calls to folks all over the globe has persuaded millions of people to install the software; the ease of use and surprising voice quality have earned Skype a loyal user base and accolades that include a CNET Editors' Choice and a Webby. #9 REAL PLAYER Ten years ago, the Web was full of static content. The 1995 debut of RealPlayer changed all that. Streaming audio and video in a free media player was a bold step forward into making the Internet a viable entertainment platform, and RealNetworks was there. Today the software plays almost every media format, and the online music store sells tunes compatible with most MP3 players--even the iPod. RealPlayer hasn't always been at the head of the class, but it was there first, and it keeps adapting to the developing world of online media. #10 ACROBAT READER Bridging the gap between print and Internet publishing, Adobe's portable document format (PDF) lets publishers distribute their articles, newsletters, and documentation online without worrying about formatting problems or unauthorized alterations. By giving away the Acrobat Reader early on, Adobe helped create a nearly unassailable market position. If you want to read magazine archives or software manuals online, you need Acrobat Reader--as its nearly seven-year occupation of the Most Popular list can attest.