I noticed that if I am looking at a post, and I connect with Twitter, then I click the 'disconnect' link, it changes the URL to remove special characters and creates a 404 error. Specifically, this URL:
http://myblog.com/2011/06/27/checking-out-hootsuite’s-new-publishing-14/
Changes to:
http://myblog.com/2011/06/27/checking-out-hootsuites-new-publishing-14/
By stripping out the apostrophe it can't find the post.