FYI: On May 22, 2012, I received a message on my dashboard pages about a problem with some of the content on my blog. I emailed WordPress.com and received word that an automated system check is in place to ensure that a blog has no more than 100 posts scheduled. What if one wants to compose more than 100 posts ahead of time? A support team member suggested putting the additional posts in draft status and scheduling/publishing them later. This seems to work.