what gets in the OED:

As a rule, a neologism needs five years of solid evidence for admission to the canon. “We need to be sure that a word has established a reasonable amount of longevity,” McPherson says. “Some things do stick around that you would never expect to stick around, and then other things, you think that will definitely be around, and everybody talks about it for six months, and then. ...”

from Cyber-Neologoliferation.

(this is a section of the NYTimes that requires registration, but I think there is free access this week.)

tsu: Thank you most kindly for that link, I've ensconced it among my Faves and shall read it carefully

However, I don't think as a dictionary compiler I'd wait five years. For instance what if the term in question gets the better part of a million Ghits

from earlier in that same article:

“Because it’s the O.E.D.,” says Fiona McPherson, a new-words editor, “once something goes in, it cannot ever come out again.” In this respect, you could say that the O.E.D. is a roach motel (added March 2005: “Something from which it may be difficult or impossible to be extricated”).