Haloscan html sandbox
<i>italicized text goes here</i>
<b>bold text goes in here</b>
<a href=" "> </a>
<a href="http://www.whateveryouwant.com/"> link to whateveryouwant.com!</a>
Copy the HTML above the examples and paste them into your haloscan box and you should be able to make links and add emphasis to your posts, while avoiding the haloscan blowout.
Feel free to practice in the comments below.