The CASRO Code of Standards and Ethics for Survey Research has recently been amended to allow for conducting blind studies on the Web. This comes up fairly often in situations where a client has a list of their customers they wish to survey anonymously in the belief that they will get more unbiased information if respondents don't know the survey sponsor. The specific change in the new version of the code is:
The practice of “blind studies” (for sample sources where the sponsor of the study is not cited in the email solicitation) is permitted if disclosure is offered to the respondent during or after the interview. The respondent must also be offered the opportunity to “opt-out” for future research use of the sample source that was used for the email solicitation.
There are other changes to the code that I am very unhappy with. They have to do with allowing the collection of very sensitive information such as SSNs, bank account numbers, passwords, etc. But this one relative to blind studies is a positive step.