This is a bit of a trick question, if only because you should always be split testing things like ads, landing pages, and calls to action. If that sounds a bit excessive – why mess with a winning formula? – there are two good reasons:
First, you can never be sure what’s going to work in Internet advertising. Because online advertising usually represents quick decisions made by customers who might not even be aware of their own thought processes, it’s very difficult to predict success. It’s even harder to predict whether one idea will be more successful than another, which makes testing even more important.
And, there are always improvements to be made. Unless you have an ad that draws in 100% of the people who see it, and a landing page that converts 100% of that traffic you receive, there is room for improvement. And, if you are getting those kinds of results (or anything close to them), we know a lot of people who want to hear from you!
In general, Internet advertising is all about the process of measuring, refining, and improving. If you aren’t testing the different elements of your ads and follow-up materials on a continual basis, then you probably aren’t getting the results you could be.