Data detectors are one of the new features in the OS X 10.5 version of Mail. Data detectors watch for addresses, dates, and times in e-mail messages, and when found, highlight those regions of text when the mouse enters them, displaying a button to show a contextual menu. Activate the contextual menu, and you can create new iCal events or Address Book contacts based on the highlighted information.
While I find the data detectors very useful, some people don’t find them useful at all. If, for instance, you don’t use iCal to manage your schedule or Address Book to manage your contacts, you don’t have much need for data detectors in Mail. Or perhaps you just find the highlighting annoying and never use the feature, even if you use iCal and Address Book. Regardless the reason, it turns you you can disable Mail’s data detectors. Quit Mail and open Terminal, then run this command:
defaults write com.apple.mail DisableDataDetectors YES
When you launch Mail the next time, you’ll find that iCal and Address Book data bits are no longer detected. If you ever want to re-enable this feature, quit Mail, and repeat the above Terminal command, but change
NO, then start Mail again.