Two things come to mind:
- bad guys being able to see what you’re doing
- bad guys sending you something else when you make a request to the website
Both of these cases fall under the category of what’s known as “man in the middle attacks”.
When you visit a site vía HTTPS, it’s using something called Transport Layer Security (TLS). The website encrypts and signs the data coming from it, and your browser verifies that the site is who they say they are and ensures that the data wasn’t tampered with.
Let’s say you visited a site with HTTP (that is, no TLS)… an attacker can sit between you and the real website. They can masquerade as the website and when you go to download that application to your machine, can serve malware to you instead. They also have the opportunity to read anything you’re seeing/doing on the website.
If you’re just going to read some random article and the site is http, there’s unlikely to be any real consequences. These days though, there really isn’t any reason not to use TLS, it’s just so easy.
Nah been getting rolls like that for a while now.