Airbnb has had a bumpy ride in San Francisco. After the city passed a law that required all short-term rental hosts to register with the city, only a small percentage did (thanks largely to the onerous process involved), and many of those who didn't were hit with fines totalling $1 million. Differences were set aside in January though, when the parties agreed on a way to automatically register all hosts in the city. That service rolls out today, with hosts now able to apply directly through the Airbnb site for their Short-Term Residential Rental Certificate and Business Registration Certificate, instead of schlepping down to City Hall. New hosts will only be able to list their properties once they're registered, while existing hosts will have to input their registration number to keep their listings active.