I've been trying to comment on different blogs, however after I type in my comment and post it the page becomes blank when I go back to check if my comment has been posted it doesn't appear, this happens on almost every blog!
This is a common problem i have been already facing. And have to tell you that your comment was submitted, but have to be manually approved by admin.
The comment has to be approved by the owner. This can take some time ( depending on when the owner logs in and moderates his comments)
Also make sure to clean out you computer, dump the cache. Make sure it is not your computer that is not displaying the page. Even with approved comments, there is always a message that "your comment is awaiting approval". Seems strange that it would happen with all blogs.