I wonder how accurate response times generated by these experiments are (and/or, how they define 'response time', which is sort of the same question).

E.g. if response time is defined as the time between when the visual stimulus appears on the physical screen and the time when a click or keypress is registered, there's quite some things to take into account. I don't know browser internals, but the code 'show stimulus' doesn't lead to the stimulus being on the screen immediately. Calculation takes time. Then the rendering takes time and it's normally going to take at least a couple of frames, plus extra latency introduced by some monitors, etc, before anything effectively changes on the screen. And this might not be a fixed number (best case scenario it's just noise). And there might be an unknown amount of input latency on the mouse/keyboard/touch screen/... And that all might change if you hook up a different screen or switch browser.

Now this doesn't matter a thing for toy experiments, or when doing A/B and the noise is the same for A and B, but suppose you want to do an actual experiment to measure response time to a simple and complex stimulus and for some reason the complex stimulus consequently takes a longer time to make it to the screen whereas the subject's actual response time remains the same, but you start measuring from the time where you sent the 'calculate and show stimulus' command, you might draw the wrong conclusion. From experience I know such mistakes get made, and if lucky they get discovered before publishing. But I wouldn't be certain that is always the case.

Not to be confused with the software that most labs use, http://psychtoolbox.org/ ...

Check this out: http://cognitivefun.net/

In the Deary-Liewald task my score was:

Simple task: 246 ms (with 0 error)

Choice task: 482 ms (with 2-3 errors)

How to interpret this result? How much intelligence do I have..

This is awesome! Can we get our hands on the data? I would be lovely to see where I fall in the distribution of scores..

Also it would also be nice to include things like age, sex etc to normalize the data?

I saw website and ran first demo. But in depth, I am confused, about how can I or anyone normal guy can understand the concept of this project ?

Or use one of those toolboxes to create your psychology experiments: jsPsych, lab.js, OSWeb/OpenSesame.

And to put it online: JATOS.

Does this offer any functionality above Qualtrics?

Does this package do your p-hacking for you too?

Someone please volunteer to help this person properly graphically design these experiments before they get established as some kind of standard :'-/

Reminder: psychology is not a scientific discipline.