I rarely need to join other sites these days as it seems almost all survey originators route to other sites. On Swagbucks I've had cint, Springboard, Toluna, GTM, one opinion, iPsos, and a bunch more I can't remember off the top of my head. Of course pay can differ among sites especially for routed surveys which pay less at times. So the comment above about them all being in it together has some truth to it.