What the hell is grammar anyway?

I feel like a real academic today, as I just now indirectly (with Roger) won a bet over whether a sentence like "He needs showing the way" could be acceptable. The answer is that, at least according to Google, it can in British English:

kewell needs showing the exit door

as a resource for someone who's really getting to grips with CSS and needs 'showing the light' then this is an ideal purchase.

But this brings up an important point that is incessantly being brought up anymore: what does it mean to say "This sentence isn't ungrammatical; I found it on Google"?

(1) Discussion of Columbus, his men and the food the ate.
(2) i end up with this undertaking, floured thoroughly the cloth made the little pre done seed blocks.

First off, we obviously can't just make this claim without a little bit of analysis. (1) is a sentence I found on Google, from an academic site no less. More relevant to this blog, perhaps, is sentence (2), generated by the TPS in an earlier post. Both of these could be found on Google, though neither would be considered grammatical. So in making the "found online = grammatical" claim, one must obviously impose some sort of sanity check on the data to make sure it is not a typo (as I presume the first sentence is) or a blog-making robot's sentence (as I am almost certain the second sentence is) So let's set a ground rule:

An internet example is valid if an (or better, a few) unbiased native speaker does not consider the sentence ungrammatical.

This is sort of a combination of Labov's (1975) Consensus Principle (unless you have reason to think otherwise, assume one native speaker agrees with all the rest) and Experimenter Principle (in unclear cases, trust the judgment of someone unfamiliar with the theory over someone familiar with the theory).

Those sentences would definitely not be accepted by unbiased native speakers. So with this principle in hand, we don't have to worry about absurd sentences be argued for by appearances in Google. (This is, as far as I can tell, the gist of Joan Bresnan's response to Ivan Sag's comment that teh appears millions of times on the Web but should not be considered a word of English.)

Finding something on Google, then, is not evidence in and of itself of the grammaticality or ungrammaticality of a sentence. Rather, a Google search points out instances of a construction or sentence that may be valid. The Google search, like any other corpus search, just gives us a direction to go. If one of the found sentences is clearly grammatical, then it answers our question. If there is no clear valid example of a construction/sentence, then the question remains open.

Does this seem like a reasonable framework to employ for online searches? I feel like this isn't controversial, but at the same time I think it's not as strong as we could go on what can be accepted as "grammatical" from a Google search. And what do you think is a good meaning for "grammatical"? I'm having an awfully hard time formulating a definition and would be interested in what you guys think.