A Page Is Not a Single File
When your browser opens an address, it receives a short document that describes the page rather than containing all of it. That document lists the other things the browser should go and collect: the stylesheet, the fonts, the photographs, the scripts that make menus open, and, on most commercial sites, a set of advertising slots and measurement scripts supplied by other companies entirely.
Each of those entries is a separate errand. The browser sends off dozens of them, waits for whatever comes back, and rearranges the page as the pieces land. The article you came to read is usually one of the first arrivals. The advertising elements, which often have to ask a second server which advert to show before they can show anything, are usually among the last.
That ordering explains a lot of everyday browsing behaviour. It is why a page can look finished and then reflow. It is why a paragraph occasionally moves under your thumb on a phone. It is why the little spinner in the browser tab keeps turning long after you have started reading, and why a page that felt instant on a home connection feels slower on a train.
None of this is unusual or improper. Advertising is how a great many sites are funded, and the arrangement is out in the open. It is simply worth knowing that the pieces are separate, because that is the part you get some say over.
Where the Extra Requests Come From
A commercial page will usually carry three kinds of additional element. There are the advertising slots themselves, which reserve a space and then fill it. There are measurement scripts, which record which pages were opened and for how long, so that publishers and advertisers can count what happened. And there are the assets those two bring with them: images, video players, fonts and further scripts loaded from other domains.
These additional requests can add to page activity, but their size and effect vary widely by website, device and connection. A blocker may stop some requests; this publisher does not promise a particular loading-time, data-use or device-performance improvement.
A Closer Look at Total Adblock
Total Adblock is a browser extension, listed on the Chrome Web Store by Total Security, and it works on exactly that list of errands.
It sits in the browser and compares each request a page makes against a set of filter lists. Requests that match a known advertising or tracking pattern are not sent, and the elements that would have held them are collapsed so they leave no gap behind.
The article, the photographs and the site's own layout are untouched, because those are not on the list. Here is how the main pieces work in practice.
