"...by allowing [name removed] to collect information about your internet browsing and purchasing activity."

Sure, want my bank info, blood sample and my first born?

It is NOT the job of ClixSense to protect your personal info on your system, but are these survey company's looked into first? Doing as this survey ask is in no way safe for your personal info.

Surrender totally .............and never forget to give all paswords to
They are honest criminals

My guess that this company would want you to install their application, and that they would pay you $X/week in exchange for your browsing history.

It's something I would DEFINITELY not do, but some people will still take it.

Mind disclosing the first 1-2 letters of the survey company?

I would, but when posting comments like this one I've had accounts limits set to even closing my account.

I've not known CS to do that but it could be done so I'll not give any more of a clue then I have already.
But, I will say when doing survey's people really do need to read them. Most don't pay if you don't anyway.

use your instinct go with your gut feeling.

I've never done this type of survey. The companies like Nielson are pretty well known so I'm sure they would not get private info off your computer. However, I'm always afraid that installing anything new on my computer could impact its speed or efficiency. So I err on the side of caution.