Changing your nickname doesn't help to hide
The profile ID remains the same:
For example:
https://bitcointalk.org/index.php?action=profile;u=547435You can hide your identity only by deleting your account. But deleting option is no longer supported by the forum
Even the great Anonymous (first deleted user on bitcointalk) could be identified (former nicknames are "Immanuel Go" and "Atlas") by quoted posts
Yeah, I know it, but still some people think it's better than not doing anything. I don't know, maybe previously they signed up with their real name or there was something else what can reveal their identity. Though, once you publish something on internet, it's almost impossible to hide your traces completely.