Last year Google rolled out what was effectively a built-in adblocker for Chrome — though it only applied to "intrusive" ads that didn't meet the standards set by the Coalition for Better Ads. Initially, this only affected sites in North America and Europe, but yesterday the Coalition for Better Ads (read: Google) announced that it's expanding this to all countries later this year.
Chrome has been ostensibly blocking these "intrusive" ads for many of us since last year, but it will start following the same behavior in the rest of the world beginning on July 9th. For more information on precisely what sort of advertisements will be (and are) blocked, Google has put together a short video that provides good examples, as well as the process it takes while reviewing sites.
If you haven't seen much of a difference in ads served to you since Google implemented this change, that's probably because less than 1% of the "millions" of sites Google has reviewed have seen filtered ads, and more than two-thirds of publishers found to be non-compliant with the Better Ads Standards have returned to good standing.
While some of the types of ads Google and the Coalition for Better Ads approve of may still be a bit too obnoxious for some tastes, some effort to prevent bad advertisements is better than nothing. Even if Google's own ad platform and its lack of human-reviewed content are more often than not the source of intrusive ads to begin with.