Free information on the web isn’t free; there are costs to provide it. Pop-ups: advertising, offers, and social media, are all part of the “cost” of free.
If an ad claims that they will fix your computer for free, be skeptical. You know they are trying to make money, and besides you may be able to handle the problem yourself, for free.
Of course Gmail can read your email. How else would they be able to filter it for spam? But “who” or “what” is reading it, and does it really matter?
This sounds like an advertisement coming from the website. Advertising funds websites that deliver otherwise free information. If you don’t want to look at it, you have only a few options.
Advertisements, just like in newspapers or magazines, are nothing more than rented space on a page and should never be confused with recommendations.