I do not collect any data. Simple as that.
Google ADS , YOUTUBE video’s and Gravatar Icons can and probably do collect some information about visitors, more information about that you can find on google’s / youtube’s / gravatar’s website.
Embedded content from other websites
The same as above, if there is a youtube video (example) on our website, then youtube will be collecting some statistical and maybe other information, about that you can read on the website of youtube.