The Flash technology allows you to create entire websites, animations and separate navigation items. It can be used in various parts of your design. Although the Flash vector images are compact and files are compressed when published, it may take some time to load. Therefore, minimizing the size of your Flash videos will significantly reduce the loading time for your website. It depends on the images used in your Flash web site, but basically the vector objects are loading faster than the raster graphics.
Flash is mainly used to create vector graphics-based animation programs with full-screen navigation interfaces, graphic illustrations and simple interactivity in a file format that is small enough to stream across a normal modem connection.
The Flash code is more secure that the HTML one, since it is compiled in SWF files and can not be listed in the browser.
The Flash software allows faster and easier to create web sites with a higher level of interaction than the combination of HTML and AJAX for example. The Flash web sites are non-browser dependable and they will look the same on all the browsers. Also, Flash movies can be easily embedded in your web site code.