have agreed to be part of the Presidential panel. They survey 1/7th out of that group each day..
http://cesrusc.org/election/
The Daybreak Poll is based on an internet probability panel survey. Daybreak Poll members are participants in the ongoing UAS internet probability panel of about 5,500 U.S. residents who were randomly selected from among all households in the United States. Members of recruited households that did not have internet access were provided with tablets and internet service. The UAS panel is still growing. We project it will reach about 6000 members in the coming months.
More than 3200 UAS panel members so far (July 2016) have agreed to participate in answering questions about the election, and we expect that number will increase over time. Each day, 1/7th of those who have agreed to participate (more than 400 per day) are invited to answer three predictive questions: What is the percent chance that... (1) you will vote in the presidential election? (2) if you were to vote, you will vote for Clinton, Trump, or someone else (percentages add to 100) and (3) Clinton, Trump or someone else will win (percentages add to 100). The order of the candidates in the questions is randomized so that about half of the respondents see Clinton as the first choice and half of the respondents see Trump as the first choice.