I went to the progressive homepage the other day and noticed an obvious split test example. Right now, Progressive is running a 3 state split test on home page content and layout.

Test 1 focuses on messaging around protection and includes an orange highlight variant
Test 2 focuses on messaging around rate quotes and features a 'complete' this sentence' style input form
Test 3 has stronger rate language and a more traditional form design

Which one will convert the best? A better question is, why don't more organizations test content, design, layout variations on their web properties? Digital testing functionality has matured to the point where it no longer takes custom programming or developer involvement. The common benefit point of being able to 'listen' to your audience at scale is the ability to quickly optimize messaging by swapping out lesser performing content for content that proves to resonate better with your audience. Another benefit, which folks don't realize until they start testing is that it actually improves the intuition of the marketer. All testing starts with some form of hypothesis that the marketer leads with.

I wonder what button color would convert better; orange or blue?

What compels our audience to convert to a first time customer; product reviews or shipping options?

Jeff Bezos has a pretty popular quote -- 'For every leader in the company, not just for me, there are decisions that can be made by analysis. These are the best kinds of decisions!' That pretty well sums up the rationale for testing within your digital properties.

Many enterprise systems include testing functionality, either built into the system or as an integrated module.

Sitecore makes enables testing through DMS and Sitecore 8.0 has moved its testing functionality directly into the content editing workspace. The rationale is that, if you're adding/editing content, you should be continually thinking about optimization.
Kentico's testing functionality is also built into their page editor. It's available for customers that have licensed the EMS edition.

With enterprise systems that include the testing functionality you enjoy the benefit of being able to automatically convert winning tests content into permanent content. You can also see test results within the analytics area of the system.

If you have a WCM that doesn't include A/B or multivariate testing functionality can use services like:

If you're not testing content regularly, you're missing out on a very valuable feedback loop. Let your customer tell you what's important to them. You'll both end up with a better experience.