Academics: one-year replacement job: kiss of death?

Hi, nerds.
Ok, so I have this pal from grad school who has taken one of those one-year replacement gigs in which universities hire someone quickly to teach classes after a sudden faculty departure while they do a more comprehensive candidate search. He really likes the school he’s working and at and would really like the tenure-track appointment. However, neither of us can think of any situation in our immediate experiences where the one-year replacement person got the job (actually another colleague has seen one instance in which it worked out but I, for example, have seen it not work maybe 5 times-- only once was the person even on the short list. However, all those individuals were also slightly insane, so it might be a separate issue and perhaps my group of subjects is not representative.)
So, fellow doper nerds-- testimonials or anecdotes. Is the one-year replacement gig the kiss of death, or is it a foot in the door? It seems like a very very long, unofficial on-campus interview to me. And besides, the hot mysterious bike messenger in the lycra tights always seems more attractive than your current long-term boyfriend (my current metaphor). Has anyone ever seen this work out? In the last 10 years?

I’ve seen it work out several times. I’m an academic librarian, but I’ve known teaching professors who started as temps; if the university likes them AND has the money they’ll usually try to create a position for them when the temp one is gone.

Most colleges have a written policy of always letting professors know their contracts will not be renewed at least three months (usually more) ahead of time so they can seek other employment. If the person takes the temp job and it’s not a love connection or the money isn’t there they’ll usually have time to find something. It’s certainly no black mark on a record because at the next interview they simply tell the truth: it was a one year appointment.