You can configure Opera Mini to render your website on Operas servers and send a static (super small) version to your mobile phones browser. This is really good when you have a slow connection and pay for the amount of data. According to Opera: Mobile internet users in Africa have already saved $500,000,000 over the last 10 months, while using the Opera Mini mobile browser and there are also a large user base in India.
The mobile web has room for improvement to work better and look better in Opera Mini. These are listed as blocking tasks.