The currency rates are not a random walk (it's easy to verify that emprirically) either before or after adjusting for the interest rate parity.
What makes currency markets different is that they have huge powerful players -- central banks -- which are not driven by the profit motive.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.