We have already generated profiles!
Steamid64 also looks up other useful profile information such as total games owned, steam level, profile visibility, and more. There is also an option to sign in through Steam, which gives grants even more options and features.
When you use the “Log In Through Steam” option, Valve gives the site your public profile information, steamid64.net does store your public profile information, but we do not store any other user information. We only use this information for statistical purposes and to display your profile stats.
Software may use it to link your account to player data. A typical game server for example contains a ban- admin- and donatorlist. These lists consist of Steam IDs, just to make sure the correct player gets the permissions.
See FAQ for more information.