Robert_Charlton - 9:21 pm on Sep 21, 2011 (gmt 0)

This has been around for quite a while, first as an Advanced Search feature in 2010, and then as a sidebar feature.

In the March 2011 update thread [webmasterworld.com...] in a March 24, 2011 post, tedster mentioned it as one of the factors he was watching....

Some other on-page areas I'm exploring: 1. Reading level (Google rolled this information into the SERPs after they started work on Panda this past year) 2. Semantic richness, as detailed in the phrase-based indexing patents 3. Spelling and grammar.

There's also this discussion, among others...

Reading Level and Panda
Apr 19, 2011
http://www.webmasterworld.com/google/4300397.htm [webmasterworld.com]

I think that reading level needs to be appropriate to the kind of query vocabulary you're targeting. I'm sure it also ties in with user demographics.