When I was in college I bought an iMac G4, threw Debian on it, and used it for homework. I wrote a lot of OCaml on that thing but didn't do much web browsing because the lack of hardware graphics acceleration and 700Mhz clock made the then-modern web a bit of a struggle. Amusingly enough it did have enough horsepower to play Marathon via Aleph One - that's enough to qualify it as a Mac as far as I'm concerned :-)