[rjd]

I use one as I use multiple browsers, on multiple computers, at multiple locations, with varying permissions. The social discovery is quite neat in some of them as well.

But yeah pay for one... you'd have to have a special need to pay for one. For reference the one I have been using and enjoy is Kippt (https://kippt.com)

HOWEVER their latest update has broken login on Safari if someone from kippt reads this please please fix it so I can use it on my ipad :)