Pick a plugin!
We're working on porting all the plugins to strigi analyzers to make them faster and make the results indexable. You can look at the current status here. If you feel like helping in KDE then read this tutorial or look at the code that's already available. We hope to port most of the plugins quickly.
Porting the will give KDE a great boost. Extracting metadata from files is much faster with the strigi classes. After parting the kfile_png plugin, we can extract metadata (including all comments) from a 4000 png files per second on an average laptop.