Disambiguate This!
If the Wikipedia article titled “Wikipedia in culture” is to be believed, the free, online encyclopedia's primary contribution to popular culture is as a humorous reference, particularly in U.S. cable television programming.
Topic-wise, sometimes the joke relates to Wikipedia's uneasy relationship to education, including T-shirts featuring leaping graduates thanking Wikipedia. More often than not, Wikipedia's uneven reliability is the joke, such as The Onion's classic 2006 article: “Wikipedia Celebrates 750 Years Of American Independence”.
If it has had any noticeable linguistic impact (aside from debate over the meaning of "Santorum") it is probably in the phrase “Citation needed”. But the word that I wish Wikipedia could popularize is:
Disambiguation
It's a perfectly cromulent word, and can be found in the dictionary (or at least on Dictionary.com), apparently dating to the 1960s, and unsurprisingly means:
to remove the ambiguity from; make unambiguous
And yet it's not a word that I can recall having seen prior to Wikipedia, even though I have a degree in English and very nearly earned one in journalism. In a world of ambiguity, what more could we want than disambiguation to help us understand what's real, and what matters? Well, maybe therein lies the problem: there are no easy diambiguations in the real world. But are they so easy, even on Wikipedia?
If you don't know what disambiguation is, it's pretty simple. Wikipedia has articles about many people named John Smith, most real and even some fictional. So many, I'm not even going to bother counting. Because no John Smith is considered vastly more famous than the other, none of them gets this URL:
Nope, that's the disambiguation page, where one can find, among many others:
http://en.wikipedia.org/wiki/John_Smith_(footballer_born_1855)
http://en.wikipedia.org/wiki/John_Smith_(footballer_born_1866)
And, for fans of The A-Team, there is also:
In many cases, a word will have one primary meaning, and then multiple secondary uses. This is when the parenthetical expression "(disambiguation)" comes in. One example:
Typically, articles requiring some form of disambiguation require a "disambig" note at the top of the page (called a "hatnote"). Frequently, the phrasing is "Not to be confused with..." and here is one example, which I enjoy more than most:

As you may expect, there is a lengthy guideline detailing how disambiguation pages are to be governed. But on a website where not everyone knows the rules, nor does everyone agree about the relative importance of similarly-named subjects, there can be some glitches. This is especially true when one is being implored by unknown advisers "not to be confused by" a deceptively unrelated topic.
One errant disambiguation comes to mind immediately, because I'm the one who undid it.
First, Bob Dole should well-known to any American over the age of 25, if not for being the Republican presidential nominee in 1996, then perhaps for that one Pepsi ad with Britney Spears. Meanwhile, Robert Dold is a U.S. congressman from Illinois, whom I had never heard of until very recently, although I live in DC and have worked in and around U.S. politics for a decade. (Dold has only been in Washington since 2010, so there's that.)
Then what explains the admonition not to confuse this:

With this:

Yeah, I didn't get it either. So I removed the unnecessary disambiguation from Dole's page, and I seriously doubt anyone has been wondering “What about Bob (Dold)?”
There are other interesting unbalances, however often more justified. As I recently tweeted:

Indeed, compare this:

With this:

But I'm sure that's right. Joe the Plumber is far better known, following his stint as the semi-official mascot of John McCain's 2008 presidential campaign, than is Joe Plummer, who is probably a swell guy and earns bonus points from me for being from Portland. And with Mr. the Plumber now the Republican nominee to challenge Rep. Marcy Kaptur this fall, it's looking even dimmer. Sorry, Joe (the Plummer).
But in the world of interesting disambiguations, undoubtedly this one is my favorite:

At least it doesn't tell you to not to be confused.