Infamous 'Internet Database'

I was setting options for my CD/DVD burning software and came across an option under 'Audio Ripping Options' to 'Check Internet database for tracklist' I wondered what is this database? I attempted in vain to do some google searching but was only greeted by offers to purchase software.

Whether or not this 'database' is proprietary or not, it makes me wonder if there is some publicly available database for this purpose. Surely not all the makers of this type of software maintain their own database or if so, where do they get this data in an automagical fashion?

I am writing a program on the side that will assist a friend in his conversion of many MP3s. The idea is to complete the ID3 Tag information in the header of the MP3 file, so that the properties will show the artist, tracknumber, year, songtitle, etc. Also I believe with these tags completed the said information will display on your vehicle's stereo head unit HUD.

Needless to say it would be nice to pull this info from the internet without requiring the user to tediously input the information himself I had thought about scraping it from various sites like rapshody (sp?) or Amazon .. but .. this database would be much cooler.

Any information on this legendary database?

use netstat to see what ports are open when ripping, use windump, and filter the correct ports when ripping and that should give you the IP address of the server, and then do a 'ping -a' to get the hostname, also in your traffic should be any credentials required to log on if any are required, as long as they're not transmitted over SSL, well they'll still be there, but you'll need to decrypt., but then there's CDDB, the responsibility is yours to determine the legality of searching the database without an agreement from GraceNote ...