Well, with Watson being bought by Sun (and then Sun dropping development of it) there is a void in general web services for pre-10.4 systems (and a void for less resource intensive web services altogether).
There is a lot of information on the web which is much better presented in an application format than a standard page/browser format. And as most users are still using 10.2/10.3, dashboard is not really an option. Plus dashboard is a little hard on older hardware (a straight GUI is fine for most information anyways).
Web services applications don't need to be everything to everyone (which was the idea behind Watson and it's tools), a great example of a simple web services app is OmniDictionary. It is simple, to the point, and still a better resource than Dictionary.app (OmniDictionary accesses a ton of online sources for definitions).
The thing about web services apps is that you usually have to do a scrubbing of a page for the source info... and when the page changes, it'll break the app. So being willing to take the time to make frequent updates to some apps would be a must (of course, OmniDictionary hasn't really changed since it's first incarnation back in 1999 because the sources haven't changed much in that time).
If you are looking for something to do with your time, web services applications will keep you busy. And the number of apps you could make is pretty much unlimited (specially if people commission you to build them an app designed especially for their needs).
