If and when you upgrade to Ubuntu 7.10, best you run:
sudo apt-get remove tracker-utils
There is lots about this on the web (in bits and pieces). Boils down to software that was promoted for general distribution way before is was ready.
The short form, if you are developer - you do not write a background indexer that saturates the disk, or drains a laptop battery. If you can’t get this right up front, you are not ready for general distribution. If you do not know how to keep from saturating the disk (or that you are running on battery), then you are really not ready.