A perennial topic for debate on certain mailing lists at work is rich client (i.e. desktop) software versus Web-based software. For every person that sings the praises of Web-based program such as Windows Live Mail, there's someone to wag their finger who points out that "it doesn't work offline" and "not everyone has a broadband connection". A lot of these discussions have become permathreads on the some of the mailing lists I'm one and I can recite detailed arguments for both sides in my sleep.
However I think both sides miss the point and agree more than they disagree. The fact is that highly connected societies such as the North America and Western Europe computer usage overlaps almost completely with internet usage (see Nielsen statistics for U.S. homes and Top 25 most connected countries). This trend will only increase as internet penetration spreads across developing countries emerging markets.
What is important to understand is that for a lot of computer users, their computer is an overpriced paperweight if it doesn't have an Internet connection. They can't read the news, can't talk to their friends via IM, can't download music to their iPods Zunes, can't people watch on Facebook or MySpace, can't share the pictures they just took with their digital cameras, can't catch up on the goings on at work via email, they can't look up driving directions, can't check the weather report, can't do research for any reports they have to write and the list goes on. Keeping in mind that connectivity is key is far more important than whether the user experience is provided via a desktop app written using Win32 or is a "Web 2.0" website powered by AJAX. Additionally, the value of approachability and ease of use over "features" and "richness" cannot be emphasized enough.
Taken from that perspective, a lot of things people currently consider "features" of desktop applications are actually bugs in todays Internet-connected world. For example, I have different files in the "My Documents" folders on the 3 or 4 PCs I use regularly. Copying files between PCs and keeping track of what version of what file is where is an annoyance. FolderShare to the rescue.
When I'm listening to my music on my computer I sometimes want to be able to find out what music my friends are listening to, recommend my music to friends or just find music similar to what I'm currently playing. Last.fm and iLike to the rescue.
The last time I was on vacation in Nigeria, I wanted to check up on what was going on at work but never had access to a computer with Outlook installed nor could I have actually set it up to talk to my corporate account even if I could. Outlook Web Access to the rescue.
Are these arguments for Web-based or desktop software? No. Instead they are meant to point out that improving the lives of computer users should mean finding better ways of harnessing their internet connections and their social connections to others. Sometimes this means desktop software, sometimes it will mean Web-based software and sometimes it will be both.