Pros:

There isn't much positive about 4chan. Some threads are just simple forums of various topics, but that is rare. The main use of 4Chan is causing trouble.

Cons:

4chan is mainly a website of internet trolls, they do things on babe internet strictly to ange, upset and project negative impacts towards people in the internet. They perform what are called "internet attacks." In 2006, 4chan users raided Hal Turner's phone in radio show by launching DDoS to his website, and prank calling his phones while on air. It knocked his website offline and cost thousands in bandwidth bills. In July 2010, they hacked Google and put the CJk Unicode character that is a Swastika at the top of the Hottest Trends list. It was also put in the most popular search term in the USA for over 2 hours. 4chan has also been found with threads containing child pornography and animal abuse.

Pros and Cons