Thanks to Olia Lialina for giving a name to what we're always preaching around here: General Purpose User or Turing Complete User. Let's call this person a TCU. (Not Texas Christian University.)
This is a person somewhere between the programmer/designer/hacker sneering at naive users and the inept clod most "apps" are designed for.
To give some examples from my own blogging experience:
Being a TCU means you can find my email address on the site, even though I don't have a large button that hooks into your email program.
A TCU who wants to link to a post here figures out that clicking on each post title puts a permalink in your address bar (assuming your browser hasn't disabled that), which can be copied and used as a hyperlink in a post, email, or sharing site.
A TCU who wants to "follow me" finds a feed link and adds that to an RSS reader.
A TCU has an RSS reader.
A TCU finds a way to get me a message -- a non-TCU goes on Twitter and demands I turn on blog comments.
In the scenario where Firefox takes away the checkbox to disable Javascript, the programmer sneers at the ordinary user who will get into trouble turning off Javascript, the inept clod is the person who checks and unchecks boxes without knowing what they do, and the TCU either employs the box (if it's there) or goes into about:config (if the box has been removed) but ultimately has a reason to turn off Javascript - say to visit a suspicious page or troubleshoot a web app.
If a TCU is having problems searching old tweets, he makes a Twitter archive using an open-source web-page-making program (and takes the time to save the tweets, a few dozen at a time, as he goes). Obviously this isn't worth doing if most of your tweets are just "hey dude."
Lialina mentions regularly visiting Twitter pages without following people as a TCU example -- what a concept.
The TCU complains about login attacks on his self-managed site and miraculously gets a suggestion from a generous TCU of a plugin to use (it's working).
The TCU turns off Google's "display results as you type" feature. Have a little patience, jeez.
The TCU is wary of "dark patterns" in web design -- the down side of being treated like a clod by programmers is that they can manipulate you.
The old-new academic word for TCU is bricoleur, one who cobbles together experience from available bits and pieces. Lialina is correct to put the focus back on the USER, where the drift of current design is to rub out all traces of human agency while at the same time encouraging people to express their individuality by sharing.
Will try to think of other attributes of this marvelous being without being too egotistical.