Check if backlinks have a “nofollow” attribute

Link exchanges are still one of the white hat ways to build backlinks but unfortunately, there are many unscrupulous webmasters, who will cheat you. One of the scams is when you pay somebody for a backlink, it suddenly disappears or has the “nofollow” attribute. That is why you should check from time to time if the link is still there and if it doesn't have the “nofollow” attribute.