I have complimented the Steam achievement system to be the best of its kind because it doesn't encourage Achievement/Trophy Whore-ism Syndrome which has afflicted many gamers these days without them even knowing it, but it looks like at least for a little while, that syndrome may be affecting the Steam community with the introduction of "The Great Steam Treasure Hunt" event that started yesterday. Well at least in this situation, unlocking "objectives" or the achievements actually lead to a good reward instead of some meaningless numbers on your profile. Every other day, Steam will list several activities that you can complete, some involving achievement unlocking, and each completed objective will provide you an entry into the sweepstakes where you can win the top 5 games on your wish list. If you complete any 10 of all the listed objectives and then log in to your account on the last day of the promotion, December 20th, you will be eligible to win 100 games of your choosing! Wow. It's one smart marketing promotion because the games involved will receive a price discount so that you can buy and play the games and unlock the specified objectives. The cool thing here is that even with the achievement unlocking madness involved, the credibility of Steam's leaderboard-based achievement system will still remain intact because they only want you to achieve something that you will probably be unlocking accidentally by just playing the games a little bit. Only Steam knows how to make a beneficial kind of achievement hunting!
One of the current objectives, "Self-Portrait", doesn't even require you to play a game!