What constitutes Usage Data. Is it sharing the posts I view, communities I subscribe to etc?
Does paying for a premium version stop this data being collected?
You most likely can use the account, unless the author is intentionally doing something shady, Google doesn’t know your username from this interaction.
Google doesn’t know the username of someone logged in? I thought that might be the first piece of data that Google picks up.
They have no way to know it, unless the author of the web or app lets them know.