Very...umm...contradictory!
There is no possible way to "go to painstaking efforts to make sure they get a random sample of people without any known bias" on an anonymous internet poll.
Ok I edited it to make it clear that those two sentences were talking about different polls. (I thought it was quite clear to begin with, but oh well).
Did you even look at
Harris Poll Online? They randomly email online polls to users. But the pool of users that they randomly send the poll to has already been selected to remove bias from income, age, gender, race, location, internet and computer skills, and a ton of other factors. After taking all that into account they have a non-biased pool of people to which they randomly send the poll to a few thousand. That way their polls are highly accurate.
Note: they never once ask your name, social security number, exact address, or anything else that can specifically identify you (other than your email address). So it is very anonymous.
Harris Poll's statement on their statistical analysis:
"We ask questions about your demographics, interests, employment, purchasing behaviors, and online usage to help us develop general trends about our panel. This information is used to conduct statistical analyses so we can ensure that our sample of respondents is representative of the general population. We also use this information to subdivide the panel into special interest groups and to send you surveys that are more pertinent to your interests and characteristics."
I am among the people who take the Harris polls. I like to do it since it gives useful information to companies, they can then better tailor their products to consumer's needs, and for a few minutes a week I get free gift certificates to restaurants I like every couple of months (you can choose other rewards as well).