Sure, but most of them aren't 100%, and tend to lose formatting nuances. My resume looks awful when exported to MS Word, so I always have to load it up in a pirated copy or on someone else's computer, tweak it there, and then send it on. I hate the idea of using commercial software that I haven't paid for, so it just irks me that this is required.
Yeah, but the MS Word format is vague enough, that the only way to ensure that someone else sees the same document you're seeing is to ensure that they're opening the document on the same version of Word, with the same OS and the same fonts that you have.