Sponsored links are search results that appear at the top of the list. These results are paid for by a company or individual in order to have their link appear first. Companies and individuals do this because more often than not users will click on the first link that they see after a search is made. These links can be dangerous because the link may point to a site that contains malware, spyware, or adware -- not to the user's intended destination.
Below is an example of a sponsored link that does not lead to the intended destination and could possibly contain harmful materials. Look to the right of the red arrow and notice that the first link to appear has "Ad" in a yellow box next to it. This means that the link is a sponsored link. If you look further, notice that the link is for "mozilla-firefox-free.downloadb.net/". This is not the official site to download Mozilla Firefox and may lead to a number of malicious items. The official site is the next link down to the right of the green arrow: "https://www.mozilla.org/en-US/firefox/new/". Sometimes it may be hard to differentiate between the two, so we suggest avoiding sponsored links altogether (look for the "Ad" yellow box if unsure).