If Linkvertise downloads a .exe or .dmg file to your computer during the "ad" phase, do not open it . These are often "installers" that bundle unwanted adware or browser hijackers.
The "2 Linkvertises" part means you have to repeat the ad-viewing process twice before the real link is revealed.
FastForward (available for Firefox and Edge) is a popular open-source extension that automatically skips many link shorteners.