Social: Presence
Type a username and we check whether it is free across the networks, which is worth doing before you settle on one. There are three answers, and the third matters: exists, does not exist, and the site did not answer clearly. The last one usually means the network blocked our check rather than that the name is free, so treat it as unknown and confirm by hand. Using the same handle everywhere makes you findable, which is the whole point of choosing carefully now.