MYTH: Copying and pasting your account name and password from a text file will make it impossible for a keylogger to steal your login information.
Sorry, MacGyver. It's a fairly trivial matter for many keylogging programs to check your clipboard. This is not an effective way to keep your information secure.
Myth Status: BUSTED
Saving the best for last on this one.
MYTH: Blizzard is in cahoots with gold sellers and they use them to make money off of RMT while maintaining a good public face by denouncing such transactions.
I used to see this one a lot on the forums and I think any reasonable person knows this is about as true as me being an actual talbuk.
Myth Status: Not even worth addressing.
Hope you guys can use this information, and if you have any questions of this nature (or any common myths about Blizzard), I pretty much guarantee I can give you an answer provided it won't cause any legal snafus.