This would be nice as my skill set didn't match your categories that well either.
Letting people search within the profile is a great idea, thanks! I'll try to add that in version 2 - I know the current categories are a bit restrictive, but that would be a good workaround.
But, my main areas of expertise (statistics, e.g. data analysis or mining, modeling or forecasting, designing and analyzing experiments, ...) don't mesh well with your categories. Have you thought about allowing users to search profiles, or some means of adding categories (sugestion box?)?