This prank isn't harmful, but it can still be a major nuisance. In a rare case, it could cause you to have to reboot, and almost always, it will cause you to lose your open tabs (unless you have a default set that loads each time.) While the proof of concept site mentioned above targets Safari, it can affect other browsers as well, including Google's Chrome and Mozilla's Firefox. After testing with Chrome, we were greeted to this pleasant pop-up:
The biggest issue with a prank like this is that it's extremely easy to fall victim to it. Anyone can paste a link to the malicious website through a URL shortener, and many have. If you spot such a masked URL on social media this week, it's best to click it only from trusted sources. If you're really tempted to click such a link from an unknown source, we'd recommend Google searching for a "short url expander", which will reveal the URL for you.
Over the past year, we've seen multiple examples of devices being susceptible to crashing through such simple methods. A popular go-to attack has been with SMS. Last January, the ultra-secure Blackphone was hit with such a bug, and months later, the iPhone joined the party. If that wasn't enough, Android was struck with the Stagefright MMS bug last summer.
Given all we've seen up to this point, it seems likely that these kinds of attacks are not going to go away.