San Antonio-based Rackspace, a provider of web hosting services, reported today that its Rackspace Cloud division has signed blogging service Posterous. Financial details of the win were not disclosed. Rackspace said that Posterous is using the firm's cloud services for its email processing, database, and application services. Posterous operates an online blogging service powered by email updates. Rackspace said that Posterous is planning to start storing all of the new media sent to the service on Rackspace's cloud services later this year.