when your replying to a thread, default behavior is to display you a message that your post has been completed and that you will be redirected to that post after X seconds, or you can click on a link that will bring you there if the redirect doesn't work. Some browsers/spyware/network protection blocks redirects, as hackers have found it fun to trick people into clicking on one link that looks good, but bring them to some other location that could be bad.