It's part of our anti-spam measures. To stop people coming in and drive-by linking to inappropriate sites, the system is set so that any post by someone with fewer than 10 posts that contains a link goes into moderation, which means that it doesn't appear on site until it has been approved by a moderator.
The post in question is now displaying. Sorry for this, but it does help cut down the amount of junk links that people would like to post. Sadly, the software cannot distinguish between the innocent and the guilty.
- For Teachers