I'm not sure a press release on the wires is considered a paid advertisement. Anyway, I love the comments on there! If they got any more positive there would be rainbows and hand-jobs for all!
Press releases are published by PR firms that charge companies to produce, curate and broadcast the info. The firms themselves pay fees to these services in order to be able to shoot out said info. It's more or less a crapshoot on where those releases will land - at the PR firm I used to work for, we had a couple random ones end up on some big sites.