YouTube has been subject to various controversies since its inception in 2005.
It has become one of Google's fastest growing operations in terms of sales by simplifying the process of distributing online videos, but putting some limits to the content.
However, parents, regulators, advertisers and law enforcement are increasingly concerned about the open nature of the service.
They have argued that Google must do more to banish and restrict access to inappropriate videos, whether it's propaganda from religious extremists and Russia or comic satires that seem to show children strangled by force.
Child exploitation and inappropriate content
Late last year, YouTube said it had removed more than 50 user channels and had stopped posting ads in more than 3.5 million videos since June.
In March of last year, a disturbing imitation of Peppa Pig, found by the journalist Laura June, shows a dentist with a huge syringe that takes out the character's teeth while screaming in anguish.
Ms. June only realized the violent nature of the video when her three-year-old daughter saw him at her side.
Hundreds of these disturbing videos were found on YouTube by BBC Trending in March.
Late last year, YouTube said it had removed more than 50 user channels and had stopped posting ads in more than 3.5 million videos since June. One of the videos removed was the popular YouTube channel Toy Freaks with a single father and his two daughters.
Children can easily access all of these videos through YouTube search results or recommended videos.
YouTube has become stricter about removing videos. One example is YouTube's popular Toy Freaks channel with a single father and two daughters that was eliminated last year.
Although it is not clear what exact policy violated the channel, the videos showed the girls in unusual situations that often involved simulated food games and vomiting.
The channel invented the genre of the "bad baby" and some videos showed that the girls pretended to urinate each other or remove the pacifiers from the toilet.
Ads shown next to inappropriate videos
There has been widespread criticism that the ads are shown in some clips that show child exploitation.
YouTube has now adjusted its rules about who qualifies to run ads that generate money.
Previously, channels with 10,000 total views qualified for the YouTube Partner Program, allowing creators to get some revenue from ads placed before their videos.
But the parent company of YouTube, Google, has announced that, from February 20, the channels will need 1,000 subscribers and will accumulate 4,000 hours of playback time in the last 12 months, regardless of the total number of points of view, to qualify.
This is the biggest change in the rules of advertising on the site since its inception, and it is another attempt to prevent the platform from being co-opted by bad actors & # 39; after the persistent complaints of advertisers in the last twelve months.
In November of last year, Lidl, Mars, Adidas, the manufacturer of Cadbury Mondelez, Diageo and other large companies have publicized YouTube.
An investigation found that the video sharing site showed clips of little-dressed children along with ads from leading brands.
A video of a preadolescent girl in a nightgown drew 6.5 million views.
Problems with the system to mark inappropriate videos
Another investigation in November found that YouTube's system for reporting sexual comments had serious flaws.
As a result, volunteer moderators have revealed that there could be up to 100,000 predatory accounts that leave inappropriate comments in the videos.
Users use an online form to report accounts they consider inappropriate.
Part of this process involves sending links to specific videos or comments to which they refer.
The researchers identified 28 comments that obviously violated YouTube guidelines.
According to the BBC, some include adult phone numbers or video requests to satisfy sexual fetishes.
The children in the videos appeared to be under 13, the minimum age to register an account on YouTube.