Many websites have started implementing 'Ad-Block-Blockers'. In other words, if the site detects that an advertisement did not load on their website, they open up a pop-up or other method that makes reading the website impossible until you allow ads or remove the nuisance. Personally, I hate ads (especially the annoying ones that are animated or have sound), so I just work around the nuisance - here's how you can too!
* All instructions here use Chrome, but you can do similar things in other browsers.
Step 1) Figure out the type of 'block' in place
These could be a modal, fuzzy text classes, and/or scroll-blockers. However, so long as the underlying data have already been loaded (which they usually have to because the ads would have loaded with it) then you have everything you need client-side; now you just need to remove the elements or classes in your way.
Step 2) Inspect the Page and Change/Remove Elements
Whatever type of block is in-place, you can use the browser's inspection tools to find and remove the elements (changing a lot of classes is the worst, but a find-replace will do the trick or advanced users can use GreaseMonkey/TamperMonkey to run a post-load script). In the example above, I would inspect to find that this element contains the blocker
Select the element and then delete it (Right click > Delete or Delete key). The modal is gone! Now for the scroll-block. Most sites will implement a CSS style (via class or in-line) on the body or main-content window of the site that looks like this:
That one line of code tells websites to hide scroll bars if the content expands beyond the window. If we delete that or un-check it, we get a scroll bar!
That's it! For many sites this is all you need to do. Some sites have become more complex and are beginning to do paragraph level blocks or only partial loads to test a single ad before loading all of the content, but those are few. Either way, you can generally use a few tricks within the browser to remove or fool the site pretty quickly without loading ads.