The phrase was originated on the forum, "The Pit", by (now) esteemed user, Stratoblaster73, and has now spread to be a commonly used term not only on the tubes, but in real life as well.
1. Holy shit The Dark was tits on a whale, man! (good)
2. Eughh, dude, your girlfriend fucks like tits on a whale. (bad)
1) An exclamation of surprise or shock, similiar to dayum.
2) A dismissal of something unhelpful or useless
1) A) I just won a new car!
B) Tits on a whale, that's sweet!
2) A) Hey guys, I can play "flight of the bumblebee" at 320bpm!
B) Yeah, except you've wasted your life learning a skill which is as useful as tits on a whale.
n. software that is no longer sold or supported by the original publisher / developer, often found as free downloads on the internet because it cannot be obtained elsewhere. Not legal, but often seen as morally acceptable because the company that made it is no longer selling the title, nor releasing it as freeware, therefore abandonware is "keeping the gamealive", so to speak.
Doom II is not abandonware because idstill sells it, while The Incredible Machine is not sold, therefore is abandonware.