Earlier quoted context omitted.
Mark is annoyed? How about Mark is goddamn lucky and should be both embarrassed and grateful that he's enough of a character that a chunk of the internet cares about him. Mark is annoyed? It is Mark Pilgrim's right to disappear, but to disappear in a puff of greasy black smoke and 4̶0̶4̶s̶ 410s is just attention whoring and begging people to look for him and call the police. There is no reason for Mark to be annoyed…
This doesn't make sense to me. Is there any example of a way Mark could have not been okay in a way that is helped by people on the internet tracking him down? Clearly his material was intentionally taken down.. short of "silenced by the gubbermint", I'm not sure how tracking him down could help. It seems more like voyeurism..
Of the typical signs: a sudden change in behavior, loss of interest in favored activities, setting affairs in order, withdrawing from others, self destructive behavior.
You wouldn't believe the number of suicides who, as their last and final act, cleaned up (shaved, got a hair cut, put on a suit or nice dress, put on makeup, etc.) and prior to that suddenly gave away all of their stuff particularly prized possessions (and for creative types, their lifetime collection of work).