Because you are relatively new here... new members who put links in there post sometimes need approval. Up your post count and it will no longer happen. Sorry it is just the way the site is. It helps with spammers.
As Gregdap said, it's to help against spammers. If there are links or too many special characters (i.e $%#@&*) in a post they system will mark it for review. After a few more posts you shouldn't get this issue anymore. Let us know if you need anything else.