Ever wonder why a wiki member will just disappear from a wiki, not posting activity for a year, or maybe several, before returning? Let me tell you why that is.
You see, these people are killed, by who, and why they do it, is unknown, maybe their making money off of it, I don't know. All that's known is that the people are, indeed, dead. The killer is usually an anonymous wiki contributor, who might leave a message on the victim's talk page, but usually doesn't. After about a year of background checks on the person, they'll take over the victim's wiki identity.
Usually there are excuses, like how they got caught up in real life, or they got caught up in school, or they simply forgot about the wiki. Sometimes, those who have rage-quit a wiki will even be selected, as people who quit an internet community are prone to return. Now, these are, indeed, valid excuses. After all, they could be telling the truth. But some things cannot be found from the background checks – like, for example, chats on IRCs that only two people would know about, or phone calls, which aren't recorded.
So next time one of your wiki-friends starts acting odd, next time it coincides with the anniversary of a death, well, who knows? They might be a wiki contributor.