Here is an interesting website called URLAI, which analyses the text on a given URL and provides statistics of who the writer most likely is. Of course, I couldn't resist it, so I tested this blog:
"platypuspancakes.blogspot.com is probably written by a male somewhere between 66-100 years old. The writing style is personal and happy most of the time."
I'm actually 19 years old, so that's way off the mark. The actual statistics show that my scores for each age group were pretty close together, though, so they didn't mess it up as bad as it seems from the statement.