I know we made a decision about this terminology to simplify things somewhat recently, but I don’t recall who is handling updating meta-documentation to cover this change. It’s worth noting that the Writing style guide still provides guidance for using both terms; are we not planning to make that change site-wide, or just in browser compat data?
Sheppy
I am not sure if this is the right place but IMHO, deprecated, obsolete, not-supported and not-supported-yet should be marked and highlighted.
It has happened a good few times that I have read a whole page, just to find out it was not supported by Firefox.
One can start reading from the bottom of page, but would that be proper? 
We are planning to redesign the browser compat tables, and one of the things we want to do is have a “summary compat table” at the top of the page, that highlights obvious gaps in support, and links to the full table at the bottom. So I hope that’ll help with this.
That said, page design is IMO a hard problem. There are lots of people coming to our pages from lots of backgrounds and with lots of different agendas. Slathering the pages with banners for everything anyone might find important is a recipe for a mess.
One can start reading from the bottom of page, but would that be proper?
It’s intentional that the tables are at the bottom of the pages. The idea is that the easiest places to find things are the top and the bottom, because it’s always at the same location on every page. It’s the middle that tends to be the dead zone.
Will: Thanks for the link; I forgot totally that that was going on in a GitHub issue. So many places we can have this stuff these days. 
Sheppy
I agree… I didn’t mean to change the location of the compatibility tables.
What I was suggesting was to have a banner/sticker/marker/something on top of the page to say this API is deprecated or unimplemented. Alternatively, a change of CSS colour to demonstrate the same thing would also be good.
For example, on a section like “selected” which is deprecated, I would suggest to have it in a different colour, in addition to the note beneath it.
Just found this thread; I keep using the Obsolete tag because it actually grays out the link in the sidebar, while Deprecated only adds an icon to it. In my opinion, graying out the link is much more clearer than adding an icon, because it is easy to confuse between the different icons.
An example of this would be HTMLMediaElement.initialTime, which has been removed from Firefox 5 years ago, and was never implemented in any other browser.
I can see why you want to keep the page for historical purposes, but is Deprecated really the right tag for this? Is there a way to mark it as Deprecated and still gray it out in the sidebar so no one will think about clicking on it?
That’s a question of updating the CSS to style these differently. We can certainly look at changing the style of “deprecated” items to make them dim like that, or something similar.
Eric Shepherd
Senior Technical Writer
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