Over 2 years ago we developed our own Blog. We were quite happy with it. Easy to use, and looked pretty good. Had all the features we wanted without going to a bloated Wordpress or similar type of template. Made use of a flatfile database so can be edited easily without going into an actual database.
To end user, it looked good, and was functional.
But what about search engines?
I never received any complaints from any webmaster tools, so I figured it was doing great.
However, I came across an article which made reference to schema.org. In it, it talked about news articles, job posting articles and blog articles. That got me curious.
They made reference to Google's Rich Results page to see if one's pages were perceived Rich by search engines.
So I ran my blog through this test tool and to my surprise, it couldn't find any Rich Text.
Our home-grown blog template was missing some key tags which search engines just love, such as item scope and item properties. So effective today, all the necessary tags for blogging were added and the Google tool is now happy. We are now more happy.
An important note is it did not change the format of our blog at all...it looks exactly the way it did before. The only difference is that search engines are now more happy with the results.