Harry Jones 13 December 2011 We’ve been using this technique to great effect on Top10.com. We designed a custom font file in order to cut down on file size and have full control over the symbols we use. The biggest drawback for us has been rendering and aliasing issues at small sizes. The vector icons simply don’t look as crisp as their bitmap equivalents. The data attribute tip and the idea of using the Unicode Private Use Area area are good ideas – thanks for the tips.