Google+ - we choose it for you, you can't change it, we might charge you for it, and we might also take it away at some point
also - why does G+ need to insert the /u/0 after the domain name? twitter, facebook and the rest you can simply type domain.com/username but G+ just needs to make it so much less user friendly.
Seriously, did you read any of the other comments on this thread?
Facebook: "If you select a username or similar identifier for your account or Page, we reserve the right to remove or reclaim it if we believe it is appropriate"
Twitter: "We reserve the right at all times (but will not have an obligation) to remove or refuse to distribute any Content on the Services, to suspend or terminate users, and to reclaim usernames without liability to you."
Reddit: "Service Provider or third parties may charge you fees for products or services offered for sale through the Website, and/or for access to portions of the Website or the Website as a whole" AND "Provider may, in appropriate circumstances and at its discretion, suspend or terminate the access of and take other action against users, subscribers, registrants and account holders"
Tumblr: "Tumblr reserves the right to refuse registration of, cancel, or modify a Tumblr URL in its sole discretion."
these are all terms of service considerations. you can still choose a username upon signup for almost any social media account except G+. g+ is the only service that assigns a username to you.
The /u/0 just means you're using multilogin. For example, if you log in as foo@gmail.com, and then log in as bar@gmail.com via multilogin, gmail.com/u/0/inbox/whatever will take you to foo's email, and gmail.com/u/1/inbox/whatever will take you to bar's. You can thus have adjacent tabs accessing both accounts simultaneously.
Also, /u/0 is the default; you can remove it from the URL and it'll continue working just fine.
HN - choose whatever username you want
twitter - choose whatever username you want
reddit - choose whatever username you want
tumblr - choose whatever username you want
Google+ - we choose it for you, you can't change it, we might charge you for it, and we might also take it away at some point
also - why does G+ need to insert the /u/0 after the domain name? twitter, facebook and the rest you can simply type domain.com/username but G+ just needs to make it so much less user friendly.