[Kranar]

But you can't use the same username everywhere, for example doing a Google search of my username shows accounts on other sites that are not related to me. Doing a search for your username suggests that it is also likely taken on numerous other sites, including a rock-band named FoxyGen that I'm fairly confident you are not a member of.

[foxygen]

Well, yeah, the same way you can't use the same password because some websites have weird rules about password length and characters. Doesn't change the fact that you will be able to use the same username in MOST websites, given you don't have a super common username. The only solution to this problem is a password manager, which most people won't adopt anyway.