"Male bloggers of all ages write more about politics, technology and money than do their female cohorts. Female bloggers discuss their personal lives – and use more personal writing style – much more than males do. Furthermore, for bloggers of each gender, a clear pattern of differences in content and style over age is apparent. Regardless of gender, writing style grows increasingly “male” with age: pronouns and assent/negation become scarcer, while prepositions and determiners become more frequent. Blog words are a clear hallmark of youth, while the use hyperlinks increases with age."

This quote is from academic paper Effects of Age and Gender on Blogging that employs automated techniques to analyse the content of blogs.  Mathamagenic has done a great job of listing this and other papers from recent conferences Computational Approaches to Analyzing Weblogs and the 3rd Annual Workshop on the Weblogging Ecosystem.