As a web developer you always have to keep in mind that what looks great on your box not always looks that good on your client’s or on some random visitor’s screen. This is mostly because of the different browser engines and versions.
With this in mind you might tend to avoid any newer techniques, features or elements just to be on the safe side. But this also keeps you from using shortcuts and often results in worse quality.
If you planning to use a newer feature it might help if you knew which users won’t be able to enjoy your work to the full extend. To help everyone with this problem Alexis Deveria compiled a long list of the features and how are they supported by Internet Explorer, Firefox, Safari, Chrome and Opera. This list is even searchable and customizable to your needs (e.g. exclude browsers).
I can’t thank him enough for going through all that trouble finding these information and I am certain that this list will have a top spot in my future bookmarks and maybe in your’s too.