If you do choose to unsubscribe from a survey site, you could be missing out on incentives that you won't be able to find anywhere else. Some sites have sweepstakes or drawings monthly or quarterly in amounts up to $10,000. Some surveys pay cash or award points that can be traded in for cash or merchandise. Many product-testing surveys send you products to try and keep just for filling out a survey about your household's opinion of the product. These products may not have even hit the market and yet you are able to influence the marketing, advertising, or manufacturing of the product.
If you are not signed up just for the ability to share your opinion, survey sites may actually be able to bring in a part-time income for the savvy surveyor.