First, it's worth noting that metadata can be defined in many different ways. Depending on how it's defined or how it's framed in the legislation, there are different levels to which it can be somewhat invasive or highly invasive. If you consider metadata to include, for example, a list of the websites that you visited, then even if you're not getting the content of the communications through a particular website, the fact that you go to a website can reveal a huge amount of deeply personal information.
In terms of our recommendations, depending on the definition—it does depend on the definition—metadata can be an incredibly invasive insight into a person's life.