Rule # 1 - Browse the site regularly ... it's awesome!
Rule # 2 - Do not tack anything you saw while browsing, no matter how much you like that shaving company video or picture of Darth Vader on a unicycle. Save to Your Mint, ftw! (props to Matt)
Rule # 3 - When tacking, be aware that anything fresh off your Mashable, Lifehacker, Androinica, Make, Boing Boing, GeekDad, Wired, or Engadget feeds is likely already tacked. Check first, or risk looking unmanly by violating Rule #2.
Rule # 4 - Please diversify yours tacks. The 80's were awesome, but not "15 tacks on one page" awesome.
Rule #5 - Tack the source code, gentlemen. We don't want to have to Google that awesome picture of a rimless motorcycle. (props to Craig)
Rule # 6 - Accountability, gentlemen. It's not just for accountants. Please don't tack-spam links to your Pinterest site or eBay store. Sell us. Schmooze us. As gentlemen, we'll open our wallets when the time is right, or never at all. (props to Keith)