[derleth]

Those sources don't define correctness. Especially Strunk and White, which is pretty well debunked at this point:

http://www.languagehat.com/archives/003463.php

[Kaizyn]

Sorry, derleth. It's not a matter of someone defining correct usage. It's simply a matter of looking at the dictionary definitions of the words 'affect' and 'effect'. Affect simply means to influence while effect means to bring about.