Daily Surveys can be taken one or more times per day. This is indicated in the survey description. Other targeted surveys can be taken as you see them. Be sure to complete these when you see them. Some surveys may accept a limited number of responses from people matching your demographics, and can sometimes disappear quickly. New surveys come out all the time too!
Two-tier programs exist in the minority of affiliate programs; most are simply one-tier. Referral programs beyond two-tier resemble multi-level marketing (MLM) or network marketing but are different: Multi-level marketing (MLM) or network marketing associations tend to have more complex commission requirements/qualifications than standard affiliate programs.