A word is a word before it gets put in the dictionary. A dictionary is a subset of the language. You cannot prove something isn't a word by showing that it is not in the dictionary, but if its in the dictionary, then it is definitely a word (unless it's a lexicographical error).

I'm a big fan of saying whatever you want as long as people understand you. Shakespeare made up stuff all the time, and people got it. Meanwhile, I can't understand Steve Gillmor, even when he's using all one syllable words.

Do I detect a fellow amateur etymologist?

"Irregardless" just sounds ugly. It forces too much of a stress on the r and creates a sort of growling sound.