Many people ask about the Democratic Party's rules regarding the polling requirements for participation in the Presidential debates. The best explanation of the rules that I have been able to find is located here:
Within the above article is a link to a database that they maintain which lists all of the previous polls and does a pretty good job of explaining each candidate's current qualification status.
Participating in Online Polls:
Many online polls are shared across social media. These polls are NOT included in the list of polls that the Democratic party deems to be qualifying polls. There are many different opinions as to the value and/or danger of participating in these online polls, but it is safe to say that they are NOT qualifying polls as far as the Presidential debates are concerned. Be careful. These online polls may waste your time and capture important personal data.
Participating in Qualifying Polls:
The campaign has recommended that you CONSIDER always answering your phone because that unknown caller may very well be a survey company calling to ask for your opinion.