So what exactly does this say about me?

Check it out. Rank your favorite blogs. What a hoot!

But more seriously, I wonder what dynamic digital permutations they use in order to get this "reading level"? Is it the words themselves? The sentence structure? It would be very interesting to find out exactly what they base their scoring on.

I ran several other blogs (and other sites) through its machinations, and agreed with the outcome (for the most part). The Anglican curmudgeon was College Postgrad level, and Stand Firm was College Undergrad. But I feel like I'm in good company, because Mere Comments and T19 are also High School.

UPDATE:
I've done some research, and it looks like there are a couple of algorithmic possibilities, the Gunning-Fog Index being the most likely. I found another site that does roughly the same thing (though without the cool cut-and-paste graphic thingie!

Interpreting the Results
This service analyses the readability of all rendered content. Unfortunately, this will include navigation items, and other short items of content that do not make up the part of the page that is intended to be the subject of the readability test. These items are likely to skew the results. The difference will be minimal in situations where the copy content is much larger than the navigation items, but documents with little content but lots of navigation items will return results that aren't correct.

Readability Results
The following table contains the readability results for http://pygmypuffsandheffalumps.blogspot.com/ .

Reading Level Results
Summary Value
Total sentences 546
Total words 3674
Average words per Sentence 6.73
Words with 1 Syllable 2278
Words with 2 Syllables 681
Words with 3 Syllables 318
Words with 4 or more Syllables 397
% of word with three+ syllables 19.46%
Average Syllables per Word 1.68
Gunning Fog Index 10.48
Flesch Reading Ease 57.65
Flesch-Kincaid Grade 6.89

Gunning-Fog Index
The following is the algorithm to determine the Gunning-Fog index.
Calculate the average number of words you use per sentence.
Calculate the percentage of difficult words in the sample (words with three or more syllables).
Add the totals together, and multiply the sum by 0.4.
Algorithm: (average_words_sentence + number_words_three_syllables_plus) * 0.4
The result is your Gunning-Fog index, which is a rough measure of how many years of schooling it would take someone to understand the content. The lower the number, the more understandable the content will be to your visitors. Results over seventeen are reported as seventeen, where seventeen is considered post-graduate level.

Typical Fog Index Scores
6 - Resources
8 - TV guides, The Bible, Mark Twain
8-10 - Reader's Digest
10 - Most popular novels
11 - Time, Newsweek
14 - Wall Street Journal
15-20 - The Times, The Guardian
15-20 - Academic papers
Over 20 - Only government sites can get away with this, because you can't ignore them.
Over 30 - The government is covering something up

UPDATE AGAIN:
Because I was bored, I checked my Blog Readability again on June 24. Maybe it was the post I did on diversity, but now I rank at "College Undergrad" level! WooHoo!