Is there a unique ID for each Chrome User? So that I on my extension, can save informations on my database, with each user have their own unqiue ID?
Does that exist somehow?
EDIT: Or can I store informations locally on the users machine? This would make it possible to do the same as I want to do?
Im sure this answers your question. And for your update, Yes you can use localstorage to store info on the client computer. Hope this helps :)
Well to track how many installs of your extension, you can add the Google Analytics ID to your extension in your management area for you Chrome Extension Gallery. That will keep track of the installs and updates. Google analytics even has tracking usage, so you can add tracking information based on a specific metric (clicking, logging) etc.
If you meant for each "user" tracking, no, extensions don't identify each individual user, the only thing that is unique is the extension itself with its extension id. You can have other means of identifying a user uniquely through a third party service, such as OAuth, OpenID, or some custom stuff. Then you can associate your authentication to something locally
While identifying a user is not supported without the user actually logging into the app, you could track the install or machine. See this response of mine for details.
What is the best to identify machine/user in Google Chrome Extention?
