Online and Cyber Stalking - an Industry?

We have all heard about ‘googl-ing someone’. You look-up an old friend, teacher, or colleague. If you googled me you would get this result. You could get more fancy and add the city or the name of an employer ….

However, if you want to go beyond the usual, it seems to get a bit more tricky. What can you find out if the person you are about to go on a date with? Has he/she been married or better IS married? Is she/he really a doctor?
You get the idea.
There seems to be a whole industry that helps you to go a quick Online Stalking!
Within minutes of this thought, I found a dozen or more sites that promise “all the world’s information” just a click away. They seem to be all priced around $30 and are all very vague about what your really get:
Web-Detective, Net Vestigator, Cyber Detective, Complete Detective, Proinvstigator.

Does anyone have experience with any of them? I would be interested to know what you get for $30 in today’s connected world.
Something tells me that this is a big scam … maybe they just sell you information on how to search for someone on Google :-)