Are these "words" moving out of the elitist slang stage and into popular usage? It is hard for me to tell, because in the techie culture I work in they are ubiquitous. However, I've tried them out with my journalistic hat on and did not get yelled at. If the consensus is they are now acceptable usages, I'll say them more often, and "w00t" too.
In response to comments, I'll clarify the preceding paragraph. The class of word I'm talking about is acronyms that become (What do we call it?), normal words with an independent meaning. The most famous examples are OK, for which the origin may be lost, and snafu and fubar, whose origins are known by few that say them. I posit that FYI is also now a "normal" word, just a bit newer than the preceding.
The next ones on my list are BTW, LOL, and WTF, which I think are following the same process as OK and FYI, but are not so far along. How far along are they, though? I'm pretty sure I can't use them in a political speech or a grant proposal, but how about, say, a user manual, or a non-technical blog?