Timezone stamps

I was recently on a server, and realised that we have no way of knowing 'when' others are, and should be online. Brainstorming, we thought of doing a role style thing based on GMT (+2h, -7h, Ect.) but I thought this was rather slow, especially if you had to calibrate this to your own timezone. I was wondering that when viewing profiles (just on the list with roles and that) it could show THEIR time. This would allow you to reason 'hmm... Its 2am for them, they probably wont answer a DM, and there is no point pinging them millions of times.'

Just an idea! If its unnecessary or similar to another suggestion, ill delete it. If not, all the better!