Calum. That is a *very* good question and not one most M$ web site designers ask themselves, which causes us even more hate toward M$. There are some good references out there that will list all of the tags (similar to the link I gave you from netscape) that will list all of the tags, whether they are netscape or IE specific, what versions they were introduced in and what HTML standard they are compliant with.
Here's an example of a very good one, notice the HTML version, the IE version and the Netscape version:
http://freespace.virgin.net/sizzling.jalfrezi/frames/fi.htmYou'll notice that not just the tags can be browser specific but parameter extensions to normal tags can be browser specific. So it is very wise for you to make sure you are writing your HTML with compliancy in mind. You can tailor your HTML to check the browser and version and branch off to browser specific code but HTML can get very complex when you do this and requires the use of JavaScript. You can make a very nice web site using standards concious HTML very easily as long as you know if you are using a proprietary tag or parameter.
[ September 06, 2002: Message edited by: void main ]