I just noticed today that something seems to be creating contacts automatically for me while I read email, similar to the feature in Thunderbird that automatically adds every email address it sees to your address book. I don't know when it started doing this. I've had the phone for a year and I don't think it's been doing this the whole time, but I guess maybe it has and I never noticed before.
I have two email accounts configured. One is Exchange for work and the other is my personal Google account. These "extra" contacts I see getting created only come from the work (Exchange) email messages, not from the Google account. They are not being synced back to Exchange - I don't see them in my Outlook contacts on my PC.
I've looked in the preferences in both the Email and Contacts apps and it doesn't appear to be an option I've turned on there. Didn't see anything in the Accounts control panel either.
The phone is an unlocked GSM Pre2 running WebOS 2.2.4. I do have a few Preware patches on it, but I don't think any of them are doing it...