Miami-based startup LiveNinja offers online experts in a wide range of fields. The six-person company, which won the Miami Startup World competition at the Venture Hive incubator this year, has raised more than $500,000. It makes money by taking a 20% commission on the fees its “ninjas” earn. CEO Will Weinraub says the site combines Skype, blogging, an online payment system, scheduling services and a marketing platform for entrepreneurs. Users rate and review the services they purchase. The webinar interface runs entirely in the user’s browser. It is less expensive than other webinar platforms, and, unlike popular alternatives such as WebEX and GoToMeeting, it doesn’t require plug-ins or extra software.