The issue that you're seeing with the underlining, links and advertisement pop-ups is a browser-specific occurrence. The reason why this happens is most likely because of some kind of spyware/adware program that is installed on your computer or browser. The spyware program loads in the background and underlines certain words, which turns them into hyperlinks.
Therefore, when you click or put your mouse over them, an advertisement pops up that leads you to the product related to the word that's highlighted.
To remove the offending programs, you will need to uninstall the program as well as any of the additional side-programs that were also downloaded to your computer or try disabling any browser add-ons.