Make sure they will never ask you to buy products. Keep in mind that survey websites are only concerned with getting surveys filled out; they will not try to sell you something or make you try some product. No legitimate survey company will sell goods and/services to its participants therefore be sure to recognize this as a scammer’s identification by understanding the terms and conditions agreement.
Make sure there are no obligations. Keep in mind that the terms and conditions is actually an agreement and not an actual contract. Meaning to say, that no legitimate researching website will bind you to the panel; you should be given the freedom and choice to walk out from the panel completely or stay inactive for a while. By no means shall the terms and conditions include the clause for obligations for a user hence check your rights in the agreement before saying yes to it.
Make sure they are not a freebie site. There is a difference between surveys and freebies. Freebie sites offer gifts or money for completing offers. This is totally different from paid surveys. Before actually joining a survey panel, make sure you know how it is supposed to work. Understand with clarity that your job is to complete questionnaires (answering questions). You are not obliged to complete offers or trials etc. That is not a part of your job therefore make sure the website does not want you to do these tasks that you are not meant to do on a survey website company.
WHICH DETAILS ARE OK TO SUBMIT AND WHAT ARE NOT