Thought I’d take a moment real quick to explain how ad networks work. This isn’t strictly relative or relevant to this class but it’s kind of a neat example of how cookies are used. So say you have your browser and it makes a request to some website and you know, this website responds with some HTML. You know, one of the things in this in this HTML could actually be a little one pixel hidden image. That you don’t even see. That makes requests to somebody else. For example, Google.com. And this in fact happens. And, because Google.com has an analytic’s package set a lot of websites use to track you know, traffic and what users are doing. And that sort of thing. And google.com may, re, respond you know, it’ll respond with the actual pixel image. You know, this might be a, you know, image source equals you know, Google something. And this may have a cookie down there that will you know, assign you some ID, so that when you come back to the website again and we, you request this pixel again, Google can track that you are the same user coming back. And you know, that you know, that’s how they know whether you’re a new user or a returning user. And, and so this is you know, this is an example of, of a third party cookie. You know, we went to udacity.com in our browser. But we received a cookie for google.com. You know, Udacity doesn’t receive those cookies, but Google will, and, and that’s how they run their analytics. And, and there are legitimate uses for this. You know, analytics is a really good example. We, you know, we use Google Analytics on. You know, we use it on Reddit and we use it currently on Hipmunk, and udacity uses Google Analytics as well so we can see, you know, what our traffic is, what people are clicking on that sort of thing. There’s also more sinister uses, which is actually [LAUGH] Google is a big pro user of this. Now Google knows something about you. You know, they know that you’ve been to this website. And you may go to another website. You know, let’s say it’s, it’s pets.com and pets.com, you know, returns HTML, you know, as usual, and it has the same pixel which goes to google.com. All of a sudden Google knows hey, you’ve been to udacity.com and pets.com because they’re like a common third party here. And Google actually has, you know, between Google Analytics and Adsense and that sort of thing, they actually have pixels and presence on a huge percentage of web pages. You know they have one of the largest ad networks and so now they know this information and they can give you ads that are more relevant to you which is sometimes you know, you can argue that both ways. Oh you can say that ad’s more relevant for me, so that I am more likely to click on it and it maybe that is a good thing or it is creepy that this company knows all of these different websites that I have been to. Generally we can trust Google, you can’t say the same for all ad networks. So, anyway, that is kind of how they work. They have got these tracking pixels and when you disable third party cookies in your browser. You help disconnect yourself a little bit from, from that sort of tracking. And, you know, I don’t mean to pick on Google specifically, because, you know, they’re actually you know, not too shady. But there are a lot of shady variations of this out there. So, that’s how it works.