As far as most Web developers are concerned, symbols came onto the scene when Flash was introduced. By saving an object into Flash's symbol library, the same item could be used over and over again with very little impact on file size.
Obviously, in the case of Web graphics, smaller is generally better, as many users still access the Web through dial-up modems. Thus, a technology that intelligently recycles its content becomes a popular tool in the online world.
SVG's use of symbols offers the same value that Flash does: 1) graphics become smaller to download as more of their visual components are replicated using symbols, and 2) graphics become easier to modify when their content comprises symbols.
With such benefits, ...