Also: if you put a link in your posting: highlight it to select it, then click on the "link" tool on the toolbar. (Click image below to enlarge).
For links in comments: enter the following HTML code into the comment box:
<a href="www.google.com">Home</a>
Change "www.google.com" to whatever website you want to link to. Change "Home" to whatever text you want to display as the link.