Is this worth the time?

[helpme]

I've only been doing this a short while and already several of the sites I joined are no more.

Thorbux, Buxsimple, Mindbux.

Is this common?

[hjf040790]

Paid-To-Click sites are worth the time if you know the right sites to join (i.e. ones that are operating for more than a year and has a history of paying on time). Examples of these sites are ClixSense, Clicksia and Buxp.info. You can check my signature for more information.

[aimyours]

Hello dear "helpme",..
The two last sites you mentioned have already said "bye-bye" to us, unable to pay members anymore... 

Have you read announcement at buximple homepage several days a go..?
Yesss, instead of e-payment account trouble (closed or limited), some sites have lack of money in their "wallet" but proudly to set some high click rate per ad. (for example $0.015/click for standard/free members...) 
Soon the money drain owing to the rush of members cashout...
Nothing to do but close the site and apologize to members, if they dare ..!!
( note: some of them runaway after scamming usssss.... )

I agree with what our friend "hjf040790" told You about the stable sites..
You will see that they offer somewhat nice click rate, not too low or even too high...

Good luck with your choice and happy earning...