The FontShop has a new tool for finding fonts, TypeNavigator. It uses a multiple-choice method of selecting font features within a genre. Select "Humanist Serif", for example, and then click your choice of serif style, character width, character contrast, etc. This pulls up a search result based on fonts with the closest matching features.

At the moment, only FontFont's library is available, but according to Typographica, the Linotype collection should be live soon.

The font previews were small and the anti-aliasing was a bit jagged. I really couldn't see enough of any font details to really feel comfortable buying anything. If you want to try a custom, larger preview, you have to go back into the FontShop site and find that font again. There also could be a few more choices to refine the search further.

That being said, I think it's a great idea and a good, solid start. There are so many great typefaces out there that get missed because it difficult to search by a visual feature. Kudos to FontShop.