I’ve mentioned recently that we have to accept Google will see our web pages’ description meta tags as serving suggestions only, and will most likely select what it believes is a more relevant snippet from the page instead.
Why does it do this? As you might expect, it’s data driven. Does the description look as good as our well-crafted one? No. Does it get better clickthrough numbers? It turns out… yes. According to this article, always using our descriptions leads to a 3% loss in organic traffic.
There’s some code which can be used to tell Google not to index the copy on a page. This leaves it just the title and the description meta tag to display, effectively forcing it to use the description provided. Somebody did an A/B test using this code, because there’s always somebody, and it turns out that people prefer Google’s word salad of selected text.
So keep writing those nicely-crafted description meta tags, and include all the most likely search terms to increase their chances of being used. But don’t feel you’re losing out if Google does its own thing.