Observer
2 websites

Observer is free to use

http://observerapp.com/

Observer is a web analytic tool developed by Ludwig Pettersson. Observer also includes a toolbar that lets you view your analytics no matter what site you are on.

VS

Vizu
15 websites

Vizu is free to use

http://www.brandlift.com

Vizu Corporation provides the first real-time, enterprise technology platform that allows advertisers and their partners in the digital media ecosystem to collaborate around optimizing Brand Lift metrics, moving their target audience throug...

Market Share by Top Websites

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

Websites Categories

1 Vizu has better usage coverage in more websites categories. Including Computers Electronics & Technology, Adult, Hobbies & Leisure, News & Media and one other category.

2 Observer hasn't got a lead over Vizu in any websites category.

Geography

1 Vizu is leading in most countries, including United States, India, France, Indonesia and 4 other countries.

2 Observer is leading in Russia.