In Mail-It 3.0, there is a bug in the address book „type ahead“ search function. You should be able to type the first few letters of a person’s name, nickname, or comments, and have the set of displayed People files narrowed to just those that match those criteria. However, if you have a lot of People files without email addresses (100 of my 600 People files had no email addresses — these were relatives and old contacts that had been synched from my Palm long ago, which I kept around because the phone numbers and street addresses were still useful), those people will be shown as part of the found set, which can render address book searching nearly useless. In other words, a search like „hack“ (for Hacker) that should have shown four results was showing 104 results, which was not very helpful.
Here’s how I fixed the problem:

1. Close Mail-It.
2. Open /boot/home/people and sort your people files by email, so all the people files with blank email fields ones show up at the top. Drag this subset to a temporary folder.
3. Open a Terminal and cd to the temporary folder. Type:

    addattr META:email "foo" *

4. Back in the Tracker, drag these People files back into /boot/home/people.
5. Re-launch Mail-It and try address book searching again. All fixed.