There are many tech sites that use "welcome" ads. We use an overlay style. Other sites divert you to a separate page first and hold you there for 15 seconds or so unless you click through.
Browser pop-up settings don't work because these are technically not pop-ups. Those use a different technique.
We have serving rules in place for this type of ad that should limit them to one per day per visitor. The problem is that there are multiple campaigns running now from different vendors. The rule is being obeyed, but with four campaigns you'll get four ads in a row. You should NOT get more than four. If you are, you have a different problem.
I have asked an additional rule to be put into place that limits the ads to one per hour from any advertiser. So if you are on the site long enough, or come back frequently, you will get all the ads. During a typical visit, you should see one at most.
If you don't want the ads at all, change the cookie settings as suggested.
As to why we use these types of ads, it's because they are very high paying, in some cases up to 10x normal display advertising. When they function properly, they should be a minimal hassle.
If more people would buy things from Amazon, maybe I could reduce dependence on ads. But that's not happening, so I still need to rely on ads to pay the bills.