I'd like that you could opt-in into being aware of the experiments you are running, and be allowed to opt-out early of experiments when they don't work, or sign-up to run them permanently (as long as they are actually running) if they work great.

Although, letting users know about the experiments might also ruins some experiments as users could start assuming that the experiment really changes things. I imagine you can easily run a dummy experiment and have people talk about how much faster/slower their browser runs with it.