Unfortunately, some people use "2k4" as an abbreviation for the current year, 2004. This usage is dead wrong. We all got excited when we figured out that we could abbreviate the year 2000 as "Y2k," but it's over now. There is no longer a short and clever abbreviation for the current year: we're just going to have to write out all four digits. "2k4" and "2k5" won't be here for centuries.
Some people argue that "2k4" can be pronounced "two thousand four," so it is an acceptable written abbreviation. Eye sea they're point, butt its still knot correct.
Please, help stamp out the incorrect use of 2k4! And don't start using 2k5. Think of the children.