SERP this gives you the advantage to drive traffic to your site based on the amount of rankings you have. If you are able to reach rank one on page one of a search engine like Google for a very difficult keyword, then you will have a huge advantage of getting traffic. Different different site may show different result for SERP check these may create lead to a problem or inconvenience at this time you can do one thing you can search the ranking of your keyword perticularly.