The platform wars have returned. The past few days have brought an outbreak of hostilities between Apple and Adobe, and tensions between Twitter and the companies that make software clients that let people tweet.

The facts are different, but the underlying story is the same. Many software and internet companies aspire to be platforms for which others compete to make applications and services. Becoming a platform entrenches  them and (usually) their profitability.

The most famous beneficiary of such a network effect was, of course, Microsoft, which established Windows as the biggest PC operating system, and enjoyed years of growth as a result.

For a few years, the explosive growth of the internet – the ultimate open platform – has put many such rivalries into abeyance. Now, they are rearing up again. Read more