It would be a handy web tool if anytime there was a phone number on a web page, you could mouse-over the number, and a little popup would give you the name and address associated with the number.
Netflix has functionality like this when it comes to browsing movies - as on this page (just mouse-over the movie art) - the movie synopsis pops up. Handy!
Usually I don't have a lot of use for phone numbers on websites, but it's job-hunting season.