Firstly why would you want to post a blank thread, isn't the point of posting to get across a point, view or opinion?
Secondly I cant answer on how you make a link on another site but on AO you clik on the "http://" button, the first box that pops up is where you can enter the link text, for example 'CLIK HERE', the next box that pops up is where you put the URL of the website.

Why you want to post to another site other than AO is beyond me though