Here's the posts on the dark mark = bound until V unto death (from this you can take what you want to reference how it affect Snape's Task. The main summations of the theory, which is apparently mine, are 15993 and 36480).

~Amanda

15993 -- My post "A Dark Mark thought" in which I float the theory. To the very best of my knowledge, this was the first appearance of this.

15996 -- lea.macleod@gmx.net posted a sort of "this sounds scary but I think I disagree"--you'll have to read it and see what you think this person is saying.

16000 -- Rebecca Bohner says "this is a really horrible theory. I say "horrible" not because it doesn't make sense, but because it makes so MUCH sense that I have the most dreadful feeling JKR's going to prove you right." Goes on to explore reasons why it makes sense.

16031 -- Chris has his own thoughts of what the task is but says that the idea of the dark mark tying the destinies of the DEs to their master somehow is plausible.

16064 -- Amy Z calls the theory great but chilling, pointing out that Snape's character may be such that death may be the way he redeems himself. On the other hand, points out that "Dumbledore, for one, has said flat-out that Voldemort can't be killed (PS/SS 17). But I still see wiggle room there; there might be some way he could be all-but-destroyed, as he was before." (which Naama picks up on in 16071, pointing out that his first all-but-destruction did not hurt the DEs).

16071 -- Naama disagrees, saying that V's first defeat affected only the mark, not its bearers (the mark faded, but they were fine), although conceding that perhaps only V's actual death would affect them. Also argues that V's psychology is not one that would plan for his own death.

16145 -- elysian rebuts Naama's argument, saying that binding his servants to him until death is an action to prevent that death, by preventing their betrayal or attempt to overthrow him because that would be to destroy themselves.

32779 -- Pippin pointed out, in a "why do we cut sirius slack and not snape" type post, "We are willing to forgive Sirius because we know what kind of pressure he was under. It takes a little more thought to realize that at the point where Snape snapped out at Hermione, the Dark Mark was just starting to become visible on his arm."

36480 -- post of mine, responding to someone, where I restate the theory so the current membership can chew it up

36484 -- Porphyria says it's interesting but has her doubts

36489 -- Elirtai responds to Porphyria, arguing for the theory (nice summation of why DEs would have not have gone to V's aid, knowing he still lived somewhere), and suggesting that perhaps the DEs not only buy into V's death if he dies, but his immortality if he lives forever

36495 -- In which I *think* Eloise is agreeing with the theory, in much the same way that Rebecca Bohner did in 16000; at least, that's how I interpret "Oooh, Amanda, you've made me go all quivery inside"...

36833 -- Elkins does a massive post. About 2/3 of the way down, she addresses this theory, summarizing the discussion, wondering if the life-binding would also bind the DE's *power* to V, but ultimately deems herself convinced. Has a new support: "I find this an extremely compelling theory, particularly as I notice that not one of the Death Eaters in the graveyard scene so much as *tries* to excuse himself by means of the "But I thought you were dead" defense."

36842 -- I refute Elkins' one reservation about the binding of power.

From here I went up in to the 40,000s, when the summer hit, and at that point I was out of work and following things more closely, and don't remember it coming up again, and had to fix dinner.

Some other random notes for you:

36513 -- Finwitch posits, in response to a "meaning of Death Eater" thread in which the gist was that the Death Eaters "shared" V's death, and that a little bit of them died to keep V alive, that another reason that Snape hated Harry on sight was that Harry was responsible for that small death in himself. {This may have fed into Elkins' binding of power, but I don't know than anyone has tied those loose ends up formally yet}

From Gwen (as Lee Hillman's) post 30732, All Things Snape: "As Amanda's husband puts it, "Snape has a Past with a capital P." (Thanks, Jan!)" I remember seeing the question of whether it was my or Amy's husband--evidently mine, although I don't remember this particular comment.

By the way, the dark mark would figure in to the Missing Child theory for the Weasleys, another bit of bleedover where the work's probably been done already. If y'all decide to do a Dark Mark mini-FAQ to go in one of the conglomerate FAQs.