Gmail also ignores periods in the address. foo@gmail com, f.oo@gmail.com and fo.o@gmail.com are all the same address.
Looks like Gmail doesn't like the [bar] solution though
I use it a lot for signing up for mailing lists actually so you can tell if a company has shared your email. If my address was example@example.com, I might sign up with example+zappos@example.com. It's always worked for me.
You've totally saved me tons of time and effort