Many many years ago I had created a regional search engine and sold it for a very small amount of money. Recently, while scraping the content from a website (because we were moving CMS providers), the idea surfaced again. The scraping gave me great insight into why to use schema.org markup (http://defoenet.com/2013/08/why-use-schema-for-products/).
Fast forward to January 2015. My son was working on a website and had some questions about the coding. While helping him as well as providing him with a book to learn more, I decided once more to see about building a little search engine. After a little research a decent domain was located that had some SEO juice and just got put back out for sale – webzlinks.com
Going back to the old-school search engine way of doing things, WebzLinks only picks up the root domain (on interior pages), site title, site description, and some of the body. I figured the body would serve for information if the site description didn’t exist.
After crawling my first 1,000 domains I looked at the database. It was amazing the number of websites that have no description. Just over 40% of the website home pages had no meta description tag. This is especially surprising given the fact that this is SEO 101.