hey guys, what is the challenge circle that many of'em were talkin about? is it used for challenging other users?

if so why cant i see the challenge circle icon in cake mania?
and also i m able toc only a few games and its sayin me tat it wont support Mozilla firefox.(am using mozilla only now).

it says i hav to dwnlod java ActiveX Control in sum yellow bar near the browser, but i m unable to c tat yellow thng.

so i dwnloded it frm sum othr wbsite. but still am not gettin it!!!!!!! HELP ME PLZZZZZZZ.