LinktacularThis is a special Achievement that is harder to get than the rest as you can't get it on your own, you need help.
You will see people in Halo 3 with the Seventh Column symbol next to thier gamertag. This signifies they have a bunjie.net acct and have thier gamertag linked to thier xbox live acct via xbox.com.
If you get a ranked or social game where everyone on both sides has the seventh column symbol you get the Linktacular Achievement. This is the only way to get it.
So everyone make sure you have a bunjie.net acct and go to stats/my bunjie.net settings/profile information tab, then go down till you see the customize Halo 3 and click "show". Thats it you are on your way to getting a very rare achievement.