I am in Australia and seem to hit up trades close to when they are posted. My last 3 trades fell through from people just not responding as to what time they would then be on for the trade. Constantly missing the person. Or just a too hard basket for people to arrange a time to trade. People need to realise that we are not all on the same timezone. If this feature was added to peoples profile it may make it easier for those that aren't anywhere near the same timezone to decide whether it is worth doing the trade, or chasing the trade as i seem to be doing. Constantly trying to message and work out a mutual time for trade. My trades run out before we can arrange a mutual trade time. Frustrating.
I second Jenski's suggestion, as it would be much easier to figure out when you could trade if the person's timezone was available on their profile.
This ties into the trades being open too little time. With a big variation in timezones (say Australia x Europe) 48 hours is often too little time to meet up due to people's work and sleep schedules. So adding timezones to the profiles and expanding the trades would remedy the disadvantage of trading with people from very different timezones. Personally, I don't want to feel limited to only trade with my fellow Europeans, because I want to engage with AC-players globally C: