Hybrid mobile applications combine native and web technologies. They use a native shell application containing a web view to display web-based UIs, allowing development with web standards like HTML, CSS, and JavaScript. This provides better performance than pure web apps while reducing costs compared to purely native apps. Popular hybrid frameworks include Titanium, PhoneGap, Rhodes, jQTouch, and iUI. They support building cross-platform mobile apps for devices like iPhone, Android, BlackBerry and more.