People report abuse when they have nudity, sexist, racist or anti-religious content in it. If you someone gets reported for the first time he’ll get a warning message from the Social media platform support, they’ll ask the person to remove or delete the post with a warning that you will not post any similar content in the near future. If Second time violation is done, the account gets blocked for 24 hours. If such ill practices continue, your account gets deleted. But recent studies shows that many people are abusing Report abusing system.This is a very common practice, especially in political circles.
If someone doesn't like your content and you, they directly report you as for the spam or might be with some other reasons, this thing will be spread with their friends as well which means the system will automatically put the content of yours down and get it ban.

All the major social networking sites have teams who deal with abuse reports and complaints that are normally handled within a set time period. When you file a post as abusive/ inappropriate, it is immediately flagged to their team for review. They have their content guidelines which restricts offensive material. If posts are determined by their team to be in violation with the site’s standards then action can be taken to remove content.

However, if something is disturbing to you which is not meeting the criteria for being removed by the social network, then you can use personal control services to cut ties/block such people.

Thanks Shweta for the nice explanation.

Thousands of millions of messages/comments are posted on social networks such as Facebook, Twitter, LinkedIn and YouTube etc. Many of them are considered abusive and offensive.

Depending on the circumstances and the nature of the messages, any person can initially make a report to Facebook/LinkedIn/YouTube/Twitter etc., through report button provided by all social networks. All social network websites have dedicated teams working 24X7 to handle such cases. or else simply remove the content and/or close down the person's account.