You may have more than one user page. Additional pages in your user space are called "sub pages". They are named after your main user page, followed by a forward slash, followed by the subpage name. Like this: "User:The Transhumanist/Virtual classroom".
One subpage name in particular is reserved to be an active page checked by Mediawiki (the name of the software program which runs Wikipedia). That subpage, called "vector.js", is used to customize your user account.
If you use Firefox, and you would like to upgrade your Wikipedia user account with a useful collection of scripts, add this into your .js page:
After saving the page, press Ctrl+R.
Doing so will add the following programs or changes to your account:
Watchlist sorter - Sorts your watchlist by namespace, and also adds spaces for readability.
Lupin's Anti-vandal tool - A watchdog tool which adds the following 4 items to your toolbox menu in the sidebar on the left side of your screen:
When you visit these pages, a live, scrolling feed will begin. When filtering recent changes, only edits matching common vandalisms are listed (you can see this list at User:Lupin/badwords). If you select "All recent changes" then (nearly) every edit is listed, and if you click "Recent IP edits" then only edits by so-called anonymous IP editors are listed. "Monitor my watchlist" shows changes to your watched articles as they happen.
To check the contents of the entry, click on "show details". To hide that entry, click "hide details".
wikEd - replaces your edit window, and adds lots of editing features, like search and replace, local show changes and preview (i.e., they bypass the server), etc. I've been using it for about a week, and have found its search/replace features very useful. There are some annoying bugs, but the script places a convenient activation/deactivation button at the top of your userpage, so you can switch back and forth between using it and the default edit window. I prefer to use WikEd for search and replace operations, but I still rely on Firefox's default edit window for cutting and pasting (WikEd's bugs make cutting and pasting difficult).
Navigational Popups - This turns your mouse pointer into a crystal ball: whenever you hover the mouse over an internal link, a box will popup giving you a peek into that page (showing the topmost part of that page). And this function is recursive, in that you can do it again to a link inside the box, and inside the next box that pops from inside that box, and so on. There is also a powerful menu provided of things you can do to the page in the popup.
These can still be added to your account the old-fashioned way on your vector.js page, but installing them in My preferences takes just checking a box for each.