As it turns out, there's more to say about kitty pidgin, and thanks to all of those who've emailed and commented with additional links.
First, a great example of prior art for the commercial use of lolcats is Twitter's various error messages. That's the first place I've seen the grammar used in official (albeit informal) communications for a company.
More important is some of the additional understanding I've gained about why some forms of kitty pidgin are so delightful. Take, for example, invisible bike and its variations. Part of the delight of invisible item cat pictures is the element of surprise, the realization of where the missing item fits into the picture yields an "a-ha!" moment that's much more satisfying than a more literal image would be. This isn't surprising -- a lot of humor relies on the element of surprise.

But there's something more subtle going on here. If you've ever read Scott McCloud's Understanding Comics, you might be familiar with the concept of "closure". There are many meanings for the word closure, of course, but in comics, it represents the crucial construct of allowing your reader or viewer to make the final connection with your media. This is wonderful for many reasons -- it's trusting the intelligence and creativity of your audience, knowing that they'll make the mental connection in their minds. It's also allowing for spontaneity and inspiration, instead of constraining the ideas (or humor) of an image to merely whatever the original author created. And most importantly, leaving space for your audience to interact with something as prosaic as a cat picture is just plain fun.
Closure has long been part of the vocabulary of comics.
"See that space between the panels? That's what comics aficionados have named "the gutter!" And despite its unceremonious title, the gutter plays host to much of the magic and mystery that are at the very heart of comics...If visual iconography is the vocabulary of comics, closure is its grammar."
Of course, other media make use of closure as well -- in movies, our minds effortlessly connect each frame to those preceding and following it -- but comics requires conscious (or semiconscious), high-level closure between every frame.
You need an example. Let's go to the world's worst humorous cat pictures: The Garfield comic strip. Fantagraphics has an astounding writeup of why Garfield sucks so bad, despite what your 9-year-old self thought back in the day.
I was impressed to find that Eric Burns and The Strip Doctor broke down what is most fundamentally flawed with Garfield's humor. Redundancy. The problem with Garfield is redundancy. It's redundant. The humor is. Redundant.
I could tell you about this, but that would contradict the premise. Take a look:

Invisible captions! LOL.
Not someone I’d usually quote, but Kottke nails it on this one: “It’s ok if you enjoy pretending to talk like a cat, but don’t sucker yourself into thinking that it’s anything more than April Fools’ Day non-humor on every single day of the year.”
I think it’s safe for everybody to get over this kitty humor phase, put it behind us, and look forward to something funnier to laugh at that’s actually worth our time.
I’ll come back in a week and see if bitter realization has struck yet and forced you to move on to other topics you cover much more interestingly.
Per closure, I remember reading in one of my old Far Side compilations that the cartoon for which Larson was most often criticized was tethercat (found an image of it at http://mahi-mahi.com/images/covers/tethercat.jpg), and his understanding of this was that the comic never allowed for an end to the game. Just a cat on a string, round and round unending…
I’m hugely relieved by this post. I didn’t actually know what all these cat pictures floating about the web were supposed to be. Now I have been enlightened.
Peter, have you ever by chance read the short story “The Jaunt” by Stephen King? If you have, you will immediately know why I bring it up. Your post reminded me of the court case in that story, and the fact that when the defense attorney tried to argue that the victim wasn’t actually dead, the jury was more horrified by the mental picture of her screaming endlessly in some nether space between realities than they had been by a more mundane murder.
If you haven’t read the story, you probably think I’m nuts. :-)
Hi, im Mark and I guess im introducing myself!!
I came across this site using ‘stumble’ (Firefox) and thought all the ideas floating around here seem really interesting! (Although I don’t seem to agree with everything lol)
Well, thats me !