Optimizely
162,903 websites

Optimizely offers both free and paid options

http://www.optimizely.com/

Simple, fast, and powerful. Optimizely is a dramatically easier way for you to improve your website through A/B testing. Create an experiment in minutes with our easy-to-use visual interface with absolutely no coding or engineering required...

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Quantcast
274,085 websites

Quantcast is free to use

http://www.quantcast.com/

Quantcast helps advertisers and publishers better understand, find and access targeted audiences in real-time. Marketers use Quantcast to amplify their targeting and reach consumers who look just like their best performing customers with un...

Market Share by Top Websites

1 Quantcast is leading in Top 10K Sites, Top 100K Sites, Top 1M Sites and The Entire Web.

2 In terms of market share, Optimizely is clearly lagging behind, losing to Quantcast in all segments.

Websites Categories

1 Quantcast has better usage coverage in more websites categories. Including Arts & Entertainment, Games, Science & Education, Computers Electronics & Technology and 16 other categories.

2 Optimizely is leading in Vehicles, Finance, Business & Consumer Services and Jobs & Career.

Geography

1 Quantcast is leading in most countries, including United States, United Kingdom, Japan, France and 153 other countries.

2 Optimizely is leading in New Zealand, Austria, Cameroon, French Polynesia and 2 other countries.