XP - Somewhat Positive

[Morrus]

How can I tell who is a Copper or Silver subscriber if they haven’t put it in their title? (I’m a Silver subscriber, but I’ve never bothered to change my title at all.) Some people have different color names, but how to interpret that?

There are copper (well, a kinda dirty brown) and silver (well, a pale grey) username colours. But they're optional, and available to subscribers from their account settings. If they don't choose to make their subscription apparent in that way, there's no way for you to tell - except for looking at how much XP they give.