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.
Thrive - Thrive is an intuitive tool to manage your business using the latest trends in Project Management, Dashboards, Customer Relationship Management & Accounting
VWO - Use VWO to tweak, optimize & personalize your website with minimal IT help.
Demand Solutions - Demand Solutions provides software for forecast management, inventory planning, supply chain planning, S&OP, demand planning, and advanced planning & scheduling.
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.
Tru - Tru is a free photo organization software that makes organizing photos truly easy and effortless. Tru photo organizer is available for both Windows and Mac
AB Tasty - AB Tasty is an all-inclusive platform for conversion rate optimization, personalization, customer activation, and testing.