I understood the possible "efficiency" gains when people your write "2K" or "2K3" for the years 2000 and 2003, respectively, but I have recently seen at least one advertisement using "2K10" for 2010. Unless you have the caps lock on, typing 2K9 (assuming that one uses the uppercase "K") still takes four keystrokes because of the shift key, but one less character. 2K10 not only adds an additional keystroke but does not save any space as even in most proportional fonts, a 0 and a K are basically the same width. Is this just the advertising companies trying to still connect with "today's youth", as they do by using abbreviations like "LOL", "ROTLF" and "OMG" in ads? Is it possible that they do not see that inserting the "K" as an abbreviation into the year no longer makes sense?