What it is: A banner or large image, usually at the top of a page, that rotates between 3 or 4 different messages.

What it's not: The typical type of ad banner that you usually think of when someone says "banner." These are actually banners with messaging from the company whose website you are currently looking at, so they're not ads, per se. They're more like varying value propositions.

Why we care: Carousel banners are getting popular, especially for retail businesses. We've found, though, that they don't always perform well. Use caution with carousel banners and, as always, be sure to test to make sure you're getting the response you want.

This post is part of an ongoing Clickipedia series, defining all the terms you need to know for conversion rate optimization. Keep checking back each week to learn more, and don’t forget to check out the whole series.