Just like Facebook’s Instant Articles, Google’s Amp Websites basically loads pages in an instant. The idea is that it allows users to access content quicker, and for the most part AMP websites are a stripped down version of the main site, there pretty much only the content of the page is shown, which also helps speed up the loading process.
However some websites have taken advantage of this, and instead of showing the content, they might only post a teaser of the content and ask users to visit the main site instead, which can be rather deceptive. To cut down on the abuse, Google has announced that they will be reinforcing their AMP Policy where the content of AMP websites will have to remain largely similar to that of the main website.
According to Google, “Where we find that an AMP page doesn’t contain the same critical content as its non-AMP equivalent, we will direct our users to the non-AMP page. This does not affect Search ranking. However, these pages will not be considered for Search features that require AMP, such as the Top Stories carousel with AMP.”