I have multiple characters 30+, one of my characters has most of the in game achievements, I have played online and have a gamespy account. I have a legal copy (obviously), yet in steam profile for the game I have 0 achievements. How come?
This is common to all Borderlands players on Steam right now, as achievements are disabled/not working yet. http://forums.steampowered.com/forums/showthread.php?t=1390120
Borderlands previously did not include steam achievements. If it just came out recently, I'd give them a day or so to get database issues sorted out.
In general, you can determine whether or not a game has steam achievements by checking the community box in the right edge of the game's profile in the steam store.
Compare: http://store.steampowered.com/app/440/ (364 achievements listed)
to: http://store.steampowered.com/app/8980/ (no achievements listed)
A number of achievements (like Destroyed the Destroyer and Discovered various areas) won't be unlocked retroactively. You have to satisfy the conditions of those achievements in game. Achievements that are tied to completing missions or challenges will be unlocked retroactively when the character used to complete said mission or challenge is first played after receiving the achievements update. For instance, the character level achievements, 12 Days Of Pandora, or Get A Little Blood On The Tires were awarded to me retroactively.
well, my borderlands is a CD version, and im not sure it works on steam achievements, as it's registered as a "non-steam game". fully legit, blah de blah, got all the DLCS, done some online etc. but no achievements. a bit of a shame really, i think steam should allow you to fully register your CD copy...