Gmail's labs section is full of tools that help advanced users fine-tune the interface of the free Web mail service. What may be more impressive, though, are its tweaks for the not-so-advanced users, the kind who need a little hand-holding to keep them from firing off e-mails while intoxicated, or missives that they didn't mean to send in the first place.
To add to these two features, Google on Tuesday introduced "got the wrong Bob?", a very simple tweak that, based on first names, will give you a subtle nudge if it thinks you're sending an e-mail to someone outside of the group you usually correspond with. The alert shows up just above the subject line and asks "Did you mean: ____ instead of ____?" Clicking that link replaces the wrong e-mail address immediately.
In my testing I got it to work pretty well on family and co-workers, although it misfired a few times on groups of friends with whom I had past group e-mailing history. Obviously the more you send to certain people, the better it should get at identifying the ones who don't fit. However, I think most people aren't bound to get into this kind of trouble with Gmail's contact auto-complete suggestions which are quite good. It shows you the person's full name, and their e-mail address, making it difficult to accidentally select the wrong person. Then again, if you're in a rush, mistakes can most definitely happen.