They get clicked on more often, and carry a heavier weight in the minds of users. You want them, basically. Badly.
Mine went away temporarily, and it pays to stay on top of this sort of thing. Google slightly changed the way they interpret a site’s code when deciding if and what a snippet might be of.
In this instance, I was relying on having my Google Plus account set up to relate to this site, but suddenly needed to have a link back from the site to my Google Plus profile, in the form of an author tag in the website’s code.
It took all of 90 seconds to fix. But in the eyes of the casual searcher, I’m back punching with the big boys.
If you’d like to get ahead with snippets on your site, be sure to let me know.