Last year, Alan Masarek made news as he left Google to become Vonage’s new CEO.
AnyWho - AT&T's search by telephone number. If you enter a partial number, business numbers are listed after residential numbers, unless you selected the "businesses only" option.
FindLaw - Reverse lookup for legal professionals.
Switchboard/Intelius - Switchboard seems to have become not much more than a portal for selling access to "unlisted" phone numbers and public information searches.
Free searches include Reverse Phone Lookup, which turned out to be entirely useless. We entered a slew of publicly-listed telephone numbers here, only to be told that we would have to pay in order to find out who they belonged to.
The Unlisted & Cellphone Search option also yielded similarly useless answers. A search of our own, unlisted wireless number showed a result of it belonging to an unknown wireless carrier in St. Helena, California. I have no clue as to where St. Helena is, but it's certainly nowhere near the area that I live in, which is where the exchange is assigned. In order to get more detailed info, you are asked to shell out $15.
The Reverse Address Search is utterly worthless as well. Perhaps the most worthless "free search" website we have seen thus far. Sad, since Switchboard used to provide a fairly valuable free service. Don't waste your time.