Some of the world's biggest technology companies have been heavily criticised in a report by MPs who say the social media giants are "shamefully far from taking sufficient action".
In the damning report, MPs led by Labour MP and committee's chair Yvette Cooper, said the companies had failed to improve a "lax approach to dangerous content that can wreck lives".
While many consumers use social media as one of their first sources of news and information, public concern has grown over the extent of illegal, extremist or propagandistic content on the sites.
Most of the services singled out in the report employ a user reporting system reliant on volunteers to find and remove illegal content, arguing their sites are too large to manually vet all content within a reasonable cost.
However, the report rejected that argument, saying tech firms had shown in the past an ability to come up with ways of dealing with major problems around advertising.
The report said: "It is shameful that they have failed to use the same ingenuity to protect public safety and abide by the law as they have to protect their own income."
The MPs also found some companies, including Facebook, were far quicker to take action on illegal content once they risked reputational damage from media investigations.
Meanwhile Google was singled out for using new technology to prevent its advertisers being associated with extremist material but not "proactively" using it to remove illegal content. The report said it has "profited from hatred".
Dozens of brands withdrew their advertising from Google last month after a newspaper investigation found their products were being promoted beside images of hatred.
While the firms do respond in a timely manner to media and MPs, the response to ordinary web users reporting extreme content should be far better, the report said: "It should not rely on high level interventions for social media companies to take action; and there must be no hierarchy of service provision."
The report recommends the government undertake a wholesale review of the law around social media to make sure it is "up to date", and said this might include increasing punishments for firms which fail to take down illegal material quickly.