Spiral methodology is a incremental form of waterfall process. Running in four phases incrementally which are, determining objective, Identification and resolution of risks, development and testing and planning next iteration.
This process is highly efficient to start small and make the product grow into a highly mature and robust product which has mitigated all the risk factors and have covered vast variety of features periodically. This method is something that each and every product should follow who are evolving with the time and coming up with better technologies and advancements.
This method is really not suitable for small products but the mobile applications or website concepts with a larger vision can definitely adopt this concept and keep checking each development cycle with the risks and enhancements required to offer the same.