Problem A: Numerous existence throughout the years throughout the entire Web, perhaps with different usernames, different domain names, different aliases.
Problem B: Getting difficult to organize your private accounts and public profiles to be consolidated into one place. Where should they be seen in just one place?
We cannot change most of these accounts especially comments posted on the Web throughout the years.
As for Problem A, account password might have been forgotten, domain name might have not been renewed, aliases might have been compromised or deleted. As for Problem B, even they are accessible from one single place, search engines might still generating results with hyperlinks to those personal sites and public profiles.
Do you get what I mean?