You know the cloud is a huge industry, but you might not know how huge. According to Gartner, public cloud services will grow to become a $204 billion market this year, up from $175 billion in 2015.

Specifically, the Gartner prognosticators say that the software-as-a-service (SaaS), in which companies offer software that was designed to run in the cloud will grow about 20 percent, from $31.4 billion to $37.7 billion by the end of the year. And infrastructure-as-a-service (IaaS), in which companies use the cloud much as they would physical servers, will grow more than 38 percent, from $16.2 billion to $22.4 billion this year. IaaS is the arena where Google, Microsoft and Amazon Web Services are duking it out for such customers as Netflix and Spotify. 

We all know the cloud industry is huge and growing, but there's one finding that really surprised me. Gartner breaks out an item it calls "Cloud Advertising." It defines it this way:

Cloud-based services that support the selection, transaction and delivery of advertising and ad-related data in which content and price are determined at the time of end-user access, usually by an auction mechanism that matches bidders with advertising impressions.

In other words, the technology that supports things like Google AdWords, or shows you the same pair of boots you didn't buy on Amazon across the next several websites you visit--the type of systems delivering the ads you're seeing on this page right now. 

This cloud advertising stuff is big, big business. According to Gartner, it made up $79.4 billion of the $175 billion cloud industry in 2015. And it will account for $90.3 billion of the $204 billion cloud industry this year. That's growth of 13.6 percent. And a heckuva lot of money spent to put targeted ads in front of your specific eyes, in the desperate hope they'll be compelling enough for you to click on.

You  may find Internet advertising annoying. Or you may find it useful to have advertising targeted to you. You may appreciate the fact that advertising funds a lot of online content (such as this website) that you might otherwise have to pay for. I know I do.

However you may feel about online advertising,you have to respect the sheer size of the spending involved. It amazes me to know just how much is collectively being spent on the systems that are supposed to match ads to interested buyers. At this moment, those systems are showing me ads for Zappos and Cadillac. Only one of those is ever likely to result in a sale. But at least it's nice to know how hard they're trying to get it right.