display: run-in;

I’ve read the books, tried the examples and tested little known gems of CSS but then you read something that makes you sit there and realise that no matter what you do you have only scratched the surface. Molly Holzschlag teaches us about another one of those lesser used CSS rules; display: run-in; that really could be put to better use. But why is this not supported by Firefox? It would appear to be one of the better class’ to support. I can already see a use for it in this site, removing span div’s from the equation and making the code a little easier.