Metadata (or data about data) is how a search engine validates the relevancy of your content compared to what’s promised in the page’s code. Meta tags can be used for a number of different things, but that doesn’t mean every single one is worth including. The current area of interest is the apparent increase in the length of a meta descriptionthat Google displays on SERPs beneath a page title. Previously, a 155-character description was seen the most within page-one results. Starting in in late November 2017, Google seems to be ushering in SERPs with descriptions peaking at over 300 characters.