Phil Greenwood, who manages the development of our B2B advertising site , attended Web 2.0 in San Francisco this month and I thought his Top 10 things I Learned at Web 2.0 Expo were worth sharing with everyone. Sure we all knew most of these, but maybe not all of them and anyway, its always good to remind ourselves of whats important: 10. If 40% of your users dont say they would miss your site if it went away,