hey, great work! extremely nice and a must have add-on.
It helps add many more functionality and possibility to every joomla site, great work!

btw, it could be functional in IE6,

Just add the following CSS to your IE6-specific stylesheet

* html div#dhm-bar, *html div.dhmbox {position:fixed!important;position: absolute;
top:expression(eval(document.compatMode &&
document.compatMode=='CSS1Compat') ?
documentElement.scrollTop
+(documentElement.clientHeight-this.clientHeight)
: document.body.scrollTop
+(document.body.clientHeight-this.clientHeight));}

Also, the original FBBar stylesheet should be fine-toned:

i.e. border-bottom:solid 1px#333333;
to border-bottom:solid 1px#333333;

spacing is important as IE6 is a dumb =)

keep on!

p.s. I've never try Jomsocial, but you could try tweaking the z-index of the jomsocial tooltip and that of the FBbar, wiht the tooltip's z-index higher that FBbar, see if it's alright.