Take online time tracking applications for example. I was looking through Mixergy earlier and there was an interview with an entrepreneur who runs a time tracking app ( http://mixergy.com/tom-rossi-molehill-interview/ ) which reminded me of an interview I'd read a while ago with another entrepreneur who also runs a time tracking app ( Clockspot , http://www.fourhourworkweek.com/blog/2010/12/11/engineering-... )
And of course HN user, Amy Hoy, also blogs about her profitable time tracking SAAS app Freckle ( letsfreckle.com ).
I bet they weren't the first to come up with the idea of online time tracking applications, and more people will come up with similar businesses in the future but as long as they have some differentiation and find users (or rather, customers) its irrelevant how shiny and new the "idea" is.