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In real life, physical contact is preferred, as it is more direct and efficient, but it shouldn't be the only way of meeting someone. There are numerous cases where you won't be able to handshake, so you'll need to find other methods of communication.
The sad reality of HTML5 is that every browser does not equally support it. Especially considering the new JavaScript APIs, major or minor differences still exist among different browsers. However, even if the browser vendors decided to provide the exact same features for their current releases, there would still be people who cannot or do not want to update. According to StatCounter and W3Counter, as of March 2013, the lion's share of desktop browsing belongs to Google Chrome, followed by Microsoft Internet Explorer and Mozilla Firefox.
Internet Explorer 8 still shares 7 percent, Internet Explorer 7 shares 5 percent, and Safari 5.1 shares 3 percent. A total of 15 percent is translated to a number of customers you probably...