The European Commission has accused Google of using control of Android, its mobile operating system, to give its own apps a leg up.
Facebook keeps buying firms which could one day lure users away: first Instagram, then WhatsApp and most recently tbh, an app that lets teenagers send each other compliments anonymously.
Although Amazon is still increasing competition in aggregate, as industries from groceries to television can attest, it can also spot rivals and squeeze them from the market.
What to do? In the past, societies have tackled monopolies either by breaking them up, as with Standard Oil in 1911, or by regulating them as a public utility, as with AT&T in 1913.
Today both those approaches have big drawbacks.
The traditional tools of utilities regulation, such as price controls and profit caps, are hard to apply, since most products are free and would come at a high price in forgone investment and innovation.
Likewise, a full-scale break-up would cripple the platforms’ economies of scale, worsening the service they offer consumers.
And even then, in all likelihood one of the Googlettes or Facebabies would eventually sweep all before it as the inexorable logic of network effects reasserted itself.
The lack of a simple solution deprives politicians of easy slogans, but does not leave trustbusters impotent.
Two broad changes of thinking would go a long way towards sensibly taming the titans.
The first is to make better use of existing competition law.
Trustbusters should scrutinise mergers to gauge whether a deal is likely to neutralise a potential long-term threat, even if the target is small at the time.
Such scrutiny might have prevented Facebook’s acquisition of Instagram and Google’s of Waze, which makes navigation software.