[ZoFreX]

They're completely valid brackets to use in writing. You don't tend to see them much but using different forms of brackets can add clarity to nested brackets (i.e. when you feel the urge to expand on your text in brackets [which I frequently do {and according to Wikipedia, others do too}])

[ebrenes]

Thanks so much for this bit of knowledge, I was not aware this was the grammatically accepted means of doing this. I always tried to reformulate sentences to avoid nested "expressions" due to the confusing nesting of parenthesis.