Online Writing Resources

Over the years I've collected a few good grammar books, like The McGraw-Hill Handbook of English Grammar and Usage, and Strunk and White's classic The Elements of Style. But the source I find myself checking most often in my everyday writing life is Paul Brians' simple website, Common Errors in English Usage. What I like about this site is that it lists common errors alphabetically, making it easy to scroll through and find what you need quickly, whether it's checking the spelling of "mother lode" or looking up the difference between "discreet" and "discrete."

Another good online resource is Purdue University's Online Writing Lab, which has sections on grammar, punctuation, and academic writing. I use this one frequently as supplemental reading for my grammar class.

So, what's your favorite grammar/writing resource?