Google Instant's handy keyboard shortcuts let you quickly open the first result in searches by simply hitting the Enter key, but since Google highlights sponsored results as the first result, an overly trigger-happy Enter key can dump you to a bum result rather than the legitimate first result. As tech site How-To Geek points out, when it comes to software searches, this behaviour can lead to crapware-laden versions of legitimate open source software.
A careful user will likely notice that she's been dumped to an unofficial distributor in these instances, but it's also easy to trust Google's first result. In fact, often the first sponsored result is an ad that points to the same page as the real first result — for example, a search for Chrome results in an ad in position #1. That's the same as the result at the true first position. The takeaway: Keep your eyes open, and make sure you're heading to official download pages when you're grabbing a piece of software via search.