T.N.
A lot of the online survey companies are legitimate. Most pay you in points that can be exchanged for things, a few in cash. You can't make any real money doing this, but if you search out surveys and qualify, you could bring in an extra $20 - 50 a week.
I don't know anything about pandaresearch, but looking at their website, they appear to be a very typical online panel research company. That means that organizations hire them to survey their panel of survey takers about all sorts of topics. Some organizations pay more than others, and the most highly paid surveys are the ones that very few people will qualify for. It seems like you could make tons of money doing surveys, but in reality, you won't qualify for most of them. For example, you might need to have prostate cancer, buy groceries from a specific store, or have a mortgage loan through a certain bank to qualify for specific surveys.
It can't hurt to sign up -- unless they ask for money up front!!! No legitimate survey company asks for you to spend any money at all.
(I work in the survey industry)