How does online advertising work?
When I type in the URL bar www.publisherwebsite.com, what happens from the initial request until my page is fully displayed?
My guesses, observation and researchs brings the following elements :
- One initial request is made, asking for the html code. This code contains different ressources that will be requested by the browser.
- Among the ressources requested, there is 3rd party code (e.g. urchin.js), that will load trackers in the page to profile the user (for behavioural advertising purposes)
- Publisher will sell on an "ad exchange" spaces for advertisement
- In the meantime, trackers previously loaded will bid to get the space and display their ad.
- The highest offer get the spot, and pay the second highest offer + 1ct. Then the publisher will send a redirect code to trigger the request on the advertiser server.
Then it leads me to a few questions to get the complete picture :
- How can the publisher put "on hold" the redirecting request so that the bidding can occur?
- Does a tracker needs to be loaded on the page to bid?
- What happens if there is nobody to bid?
- Do content delivery networks have a role here?
- Did I miss something important?