Google search results have begun to display Google+ logos along with icons in rich snippets for company profiles. Your logo will be displayed even if you do not possess the rel=publisher markup.
In case you possess a Google+ page and your website is verified in your Google+ profile then you can expect your logo and icon to get displayed in search results. Your icon and logo can get displayed even without schema on your page provided you possess a verified site listing.
Google had actually announced around a month ago that they had no plans to bring publishership to their search results. Even though this feature does not utilize publisher code, the author snippet concept seems to have been applied for its search results in the form of publisher snippets. The same principle seems to have been used for Google.com.
If this is the case then many more businesses along with non-profit organizations and others will adopt the rel=publisher markup as well as Google+ in coming times. You too should check your listings to ensure that your eye-catching logos and icons are displayed in such search results.