Some Wii owners have discovered a ? data block in the channels portion of their save data. Many have wondered what it is exactly. Well, METROIDMANOFEST on the NSider forums emailed Nintendo and they gave a response:
Hello and thank you for contacting Nintendo,
As part of the system menu 3.0 update, the Wii console is now able to detect unnecessary files the system may have. When this happens, these files are displayed as a question mark (or marks) in the Data Management screen of the Wii System Settings. If your system is not displaying the question mark file, it merely means that your system did not detect any unnecessary files.
As to the User Generated Content, we were not informed exactly what this may refer to. Obviously, it could include messages or e-mails that you create. However, we do not know what else could be covered by this term.
Please keep checking our website at www.nintendo.com. If there is any additional information announce, you will see it on our site.
Thank you for your e-mail.
Nintendo of America Inc.