Caffeine helps Google produce 50 percent fresher search results than it did prior to it’s introduction. In a nutshell, Google visits your site aprox once every 3-4 days in order to list your content for people to find. My understanding is that Caffeine now allows Google to visit your site nearly once PER DAY.
What does this mean for you?? It means keeping your site up to date and offering dynamic content will be more beneficial to you and the people looking for your service. If Google visits your site, they want to find new information..so if your site is static and not updating on a regular basis, Google will loose interest.
So keep your site up to date…caffeine will like it!