Here is a list of different statuses for which I use to tell when I am online or not online.
"Online" I have nothing going on in real life that will conflict with Wikipedia. I will respond to your query usually in less than 5 minutes.
"Very Busy" I am currently very busy, either with school or something else that is occupying my time. I will probably answer your query in 24-48 hours.
"On Vacation" I am currently on vacation. (Everybody needs one sometimes.) My access to Wikipedia may be severely limited, depending on the circumstances. I will usually note if I will still be able to edit fully or not, right next to the status.
"On Wikibreak" I am currently on a wikibreak. (Everybody needs one sometimes.) I will not have access to Wikipedia, and I will not edit. I will respond to your query when I get back from my wikibreak.