Help:A page that only you can edit
The system assumes that a subpage of your userpage which ends with ".js" (for example, special:mypage/somepagename.js) is a javascript wiki-tool page. It is protected except for edits from your account or users with the custodian right.
One may use this feature in storing experimental data which should only be altered by participants. You may set up an account for the experiment team, and let everybody in the team know that password, and use that account to post experiment results on user subpages.