Ballot stuffing is one of the banes of online surveys. One
respondent with a desire to skew a survey can be quite successful,
submitting multiple responses to the same survey.
Papaya Polls we have a variety of methods to minimize the
effects of ballot box stuffers. This includes the standard "cookie"
checks, plus a few things that we'd rather keep secret.
The ultimate in online survey anti-ballot-box-stuffing features
is our Private Survey tools, which are described on another