Gender and Age in Statistics?

How is gender and age found in statistics? Like the statistics you see for Youtube videos after you click the button next to the view count or on Alexa?

Moved to GraphicRiver’s offtopic.

Youtube its done by the users that have an account with google and alexa have a tool bar i think

aaranmcguire said
Youtube its done by the users that have an account with google and alexa have a tool bar i think

Oh okay. So for Youtube it’s probably not very accurate since not everyone has an account and not everyone is signed in while watching a video, right? Plus people enter fake info or don’t change the default info.

Past data from youtube may not be perfect as you said not all people are logged in and some people lie, but now google has one central DB of users info it should get more accurate… heres a useful link to see what google thinks of you, and you can see if there right.. they are for me.

PS, you can opt out of this.. but for me, if im going to see ads I would rather get more personalised ones.

aaranmcguire said
https://www.google.com/settings/ads/onweb/

Cool link but nothing for me and I don’t see ads. =)

you should not see ads but a page like this…

aaranmcguire said
you should not see ads but a page like this…

I meant I don’t see ads cause I use Adblock on Rockmelt. As for the link, apparently Google doesn’t think I exist