I have signed up for this survey (via email offer) service, you fill out service and get Velocity points for it (different points ratio but you get Velocity eventually).
Typical short survey is 300 points (100 Velocity) when long ones can exceed 1,000+.
It all depends on how you value your time. For me, spending 15 minutes + on a survey for 100 velocity points is not worth it.
There are a whole lot of survey websites out there. Some are better and more reputable than others. I’ve dabbled in three: e-Rewards (which gives Velocity points), Red Planet (Qantas points), and Mint Surveys (Coles gift cards). In my experience, e-Rewards is the least worth it of the three. They give the fewest points, and their customer service is the least efficient (it once took a full two months for me to receive the Velocity points after I asked for them).
My subjective, personal opinion is that Mint Surveys is the best and most well-run of the three, with Red Planet not far behind. Unless you must absolutely have Velocity points, I’d look into one of the others if I were you.
You might also like to have a quick skim of this Point Hacks article from a few years ago.