Critics of online surveys say the respondents don’t represent the larger population, are not chosen randomly and because of that, results can vary widely from poll to poll. The Director of Polling at ABC (DIS) News calls them “poll-taking clubs.” Ouch.

However, despite the criticism, more companies are relying on the web to poll “multitudes” of people in part because it can be done “quickly and cheaply.”
Source: BusinessWeek