Verisign's revenues are about $1 billion/year. The COM and NET top-level domains together have about 150M names. The next biggest gTLDS are ORG with 25M, amd INFO with 12M. The biggest new TLDs are TOP with 2.9M and XYZ with 1.8M, with both bloated by firesale prices. The rest are smaller, mostly much smaller.

The biggest registrar is Godaddy whose revenue is about $2.5G/yr which includes a lot of non-registrar revenue. So I'm guessing that the total registry and registrar business is in the range of $3 to $5G (billion), growing slowly.

Meanwhile, Amazon's cloud revenue this year is about $20G, Google Cloud and Microsoft Azure both about $10G, each of which are likely to double by 2020. Facebook's revenue is around $40G, Google's is $100G, jd.com (the Chinese e-commerce company) $55G. Amazon's overall revenue is $180G, but most of that is stuff, not bits. The total Internet business is on the order of $1 trillion, with the domain business being less than 1% of that. So let us not get swelled heads.

This also reminds is that even though $100M to get control of .WEB seemed like a lot of money in the domain world, that would have been 0.15% of the cash Google currently has on hand.