Unity for web games
Auto-streaming web players and additional WWW streaming all work together to reduce load times. It's also possible to customize the loading screen colors, progress bar, and graphics.
You can export piecemeal packages from your project, giving you precise control over what to stream in and when to do it. See an example
Google Chrome Native Client
Unity supports NaCl publishing. NaCl's speed and compatibility across operating systems makes it ideal for web deployment. The Unity Web Player automatically plays in Chrome without requiring an install.
Efficient multiplatform publishing
Learn more about Unity's cross-platform development tools for complete control over the quality and performance of a game on any screen.