Quite a few people have been asking this question recently: on blog posts, should we display the original date of publication, or the date we last updated the post? Or both?

This is a very good question, and we'd love to be able to give you a definitive answer, but unfortunately it's not possible at the moment! Google's algorithm is constantly changing, and we haven't found a strong answer one way or the other.

Some clients have chosen to switch to displaying the last updated date to signal to the search engines that the content was updated recently (since Google tends to favour new content); others have included both the original publication date and the updated on date. That makes it clearer to users, but sometimes that can confuse the search engines a little.

Other clients choose to keep the "published on" date, but republish content with the current date after updating pages.

How much weight Google puts on the date might also depend on the subject of your site or the page itself, as some topics (e.g. reviews) are more time-sensitive while others are considered evergreen. 

Which date will Google display in searches? 

Google usually takes the date displayed in the post and uses it on the search engine results page (SERP). However, ultimately only Google itself determines what it displays and sometimes it chooses to show different information.

Is it easy to switch to showing the "last updated date" instead of the originally published date?

This is one of those tasks that seem like it should be really straightforward, but often isn't! It depends on your theme -- some themes allow a quick change, others require a fair bit of coding work to get the correct date to display.