Optimizely is a lower cost entry tool for anyone looking to do website testing. While their pricing structure has changed over the years it still is a pretty cost effective solution. It is easy to get tests up and running within 5 minutes once you have code placed on your site.
I love the drag and drop features of Optimizely. It makes it very easy to make simple changes to do landing page testing for my paid search campaigns. It also frees up dev time for our web team. Also, The findings from Optimizely tests are so valuable for an end customer experience.
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
Google Tag Manager - Google Tag Manager helps make tag management simple, easy and reliable by allowing marketers and webmasters to deploy website tags all in one place.
Google Analytics - Improve your website to increase conversions, improve the user experience, and make more money using Google Analytics. Measure, understand and quantify engagement on your site with customized and in-depth reports.
Impact Client - The Impact client is an advanced utility mod for Minecraft, it is based on ClientAPI and includes a...
AB Tasty - AB Tasty is an all-inclusive platform for conversion rate optimization, personalization, customer activation, and testing.
ObservePoint - Monitor, test and validate the accuracy of your web tags, critical user paths and more with ObservePoint's automated Data Quality Assurance solution.