Easy to understand and use, lot of materials and tutorials on internet. Large support from comunity. Great for beginners in test automation.

Selenium webdriver is targeted basically for the manual testers who just want to switch to automation and enhance their careers,software test engineers who already are practicing automation just use it to brush up the technologies,QA managers etc. Its kind of suite of tools to automate web browsers across multiple platforms.It can run in browsers like mozilla,safari etc and can be used to automate test cases.It can be used in various languages etc.Its a open source tool and is also platform independent in MAC,Windows and Linux.It also supports multiple languages like java,python,C# etc.

Manual QA testing elimination as selenium has better quality assurance.Very strong user support as it is open source.Easy integration with other testing framework such as Junit.Integration with CI tools as jenkins and availablity of lot of capable webdrivers.Multiple language as well as Multi browser support .