Most people are aware of Evan Weaver's (from Twitter) blog post introducing Cassandra.

http://blog.evanweaver.com/articles/2009/07/06/up-and-running-with-cassandra/

In the post he uses a example multiblog application -> a blog for multiple users.

I was wondering how would you be able to query by date for the example which would be a common scenario. 

For example, I want all blog posts from the month of January.

What schema changes would be required and how would you approach the problem using the API.