I've been concerned for a little while now that “functionality” isn't really a word – I always thought “functions” or “features” were more succinct and sounded less like someone trying to talk up what they were doing… out of curiosity I popped it into Dictionary.com, and this is one of the things I found:
>programming< Waffle for "features" or "function". The capabilities or behaviours of a program, part of a program, or system, seen as the sum of its features. Roughly, "the things it can do". Generally used in a comparative sense, e.g. "The latest update adds some useful functionality". That's right. WAFFLE. Now the trick is for me to avoid using this word in future and thus not prove myself a hypocrite. There's two things I absolutely cannot stand in thise world – hypocrites, and intolerant people.