Google and Facebook will take more than 70% of all money spent on display advertising online in the UK by 2020, according to a report suggesting the firms will soon have an effective duopoly spanning the Atlantic.The two companies already account for about three-quarters of the £18.4bn display ad market in the US, and 53% of the £4bn currently spent in the UK.
https://www.theguardian.com/media/2016/dec/15/google-facebook-uk-online-ad-revenue