Google is adding a warning for mobile search results for sites that use Flash. This means Google is going to add a note for your site's description saying "Uses Flash. May not work on your device."
This comes hot on the tails of Google's change last month where they began warning mobile users when a search result would redirect them to the homepage instead of the internal page they wanted.
If your site uses Flash, and you don't have a mobile-friendly version available, you will probably see your search referral traffic go significantly down. Let's face it, not many people are going to click through when they see that warning unless they already know your site is awesome sauce and what they are looking for.