profanity is one thing - and a on/off is a perfect solution.
but the concept of filtering ag-gy is just childish.
first it lends credence to the (incorrect) idea that we are offended by the term ag-gy. In reality most aggies I've seen on discussions on the topic don't find it demeaning in any way because it has no negative context at all. It is a (moronic) misspelling and we simply think the person using it is dumb - which is probably true. by filtering it you make people think it offends us. it is no more offensive to me than someone writing "nite" for night.
second, it does mess up other things including links sometimes that have nothing to do with ag-gy as a term, just an occurrence of letters in that order.
there are legitimate words containing ag-gy that just look dumb being filtered and ruin comprehension:
shag-gy, nag-gy, sag-gy, bag-gy, brag-gy, snag-gy. etc....granted those words might not be used a lot but when they are filtered they make that phrase stand out and generally make it unreadable. like if you were trying to talk about a sh**** dog, then people think you are saying "shi-tty" dog or something.
anyway an on/off would solve this stupidity as well.