You have a web site, a sales page where you sell your ebook. You'd like to improve your profit.
You raise the price and split test conversion rate. You notice that you can safely raise the price for 19% and keep the same conversion rate. So, you leave that price.
Next, you do some tweaking on the sales letter change the headline, do some changes on the body and make your guarantee more visible. You test and it shows 30% increase in conversions. Wow.
Now, you want get some more traffic. You write more content, for some long tail keywords.. You track the traffic increase - you got 30% increase in traffic. Done, enough work.
Can you tell what is going to happen to the profit next week?
* Assume the tests were valid, done on a good sample of traffic and the next week is not anything special by itself.