I agree that having ads use some of your information to target an ad isn't the end of the world. But I definitely disagree with your statement about Zerply's 404 page. Yes, they made one grammatical mistake (if you're willing to accept the "oh noes" slang), but they're programmers and designers, not english students. While that might suggest that they could have taken more time to review the details of their site, that doesn't mean they don't have an awesome and trustworthy service. I think you're comparing apples and oranges there.