I found this a interesting comment, from Danny Sullivan - it's not always straightforward to define what a "common name" is: "What are the best ways for people

I found this a interesting comment, from Danny Sullivan - it's not always straightforward to define what a "common name" is: "What are the best ways for people to prove their 'common name' status. Unless +50 Cent has a government ID with that name, it's pretty clear that Google made the sensible decision to let him use his stage name, which he's commonly known by, here rather than a legal name. But if you're not as well known as him, asking for things like government IDs to prove your 'common name' -- which you do allow -- seems difficult."