Hello everyone.
This has been something that people were talking about for a while before it faded into the background. User pages are vandalised infrequently, but user pages are more personal than articles, and vandalising them feels somewhat like an invasion of someone's personal space.
There is now a new abuse filter rule that will prevent any user from editing your user pages unless you explicitly give them permission. How do you give them permission? You need to insert the {{RestrictedUserPage}} template onto the page you want to give permissions to. The editors field should be a comma-separated list of users that have editing permissions on the page.
{{RestrictedUserPage
| editors = Person A, Person B, Jeff
}}
This is a restricted user page.
This page is available for select users to edit. See {{RestrictedUserPage}} for more details.
You, admins, and other administrative people are still allowed to edit your pages, even if you don't give them permission.