Olark is a live chat widget that you drop into your site and allows you to chat with visitors through your existing IM app.
If you use WHMCS you can quickly integrate the code supplied by Olark by putting it in a smarty literal tag just before the </body> tag at the end of your footer.tpl file in your template directory:
{literal}
//SUPPLIED CODE FROM OLARK
{/literal}
If you want the name of your logged in customers to show up in the chat you can to put the following after the last block of code you added:
{if $loggedin}
{literal}
{/literal}
{/if}
If you’re not already using live chat on your site, read more and sign up to Olark here.