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.
Good spot! We are planning to do a full site audit of that stuff, just been too busy with start-up life. We have 6 full time staff and not over a thousand like others.
It's not really about the spelling error itself. It's about the fact that you don't have the time to look for things like that, because of start-up life.
My point is that if that detail is missed, I begin to worry about other, more important details - such as security and the safety of my data.
I spent 5 minutes trying to figure out what the fuss was about before I realized they fixed it! Woops.
However, a question remains: will they eventually sell out and do similar privacy-controversial decisions as LinkedIn? Will everyone have to move again? I'm sure 3 years ago LinkedIn would deny that they would do anything like their recent move, but here we are. People keep moving from a service to another, hoping that it will be better, but what's to stop the new service from doing the same tricks once it gets big enough?
You could also tone down the deliberate cuteness. "Hmm what? Oh noes, looks like..." six nothing words before getting to the point: 404. It's wasted space, tediously hip and cloying. I hazard to say most of us older than 12 aren't amused.
I actually find that when a website takes the time to create a personal and interesting 404 page, it signals the fact that they really care about user experiencer. 404 pages can be some of the most jarring things for a user and the fact that they shared some personality and helped the user get back on track says to me that the team is focused on the right things.