Browser Support for Common Advertising Use-Cases

Hello all,

As promised, I have published a list of advertising use-cases: https://github.com/w3c/web-advertising/blob/master/support_for_advertising_use_cases.md

We have already discussed most of these on our weekly calls.

I have added a table that indicates which use-cases are supported by Chrome and Safari with links to the relevant proposals. I have also added a column for "Community Proposals" with links to various proposals made by Facebook.

At the bottom of the document (and linked from each row of the table) is a brief description of each use-case.

I hope this serves as a useful mechanism for driving the conversation forward. As you'll notice there are still a great many rows with "No support" or "No solutions yet for this problem". It would be great to at least replace these cells with something like: "Browser X has affirmed that this is a valid and important use-case that they would like to find a way to support". When possible, I've tried to put that information in with links to relevant GitHub issues.

For example, on a previous call, John Wilander affirmed that preventing conversion fraud was a valid use-case that Safari would like to support. I linked to the GitHub issue he opened on the topic from that cell in the table, where we have a great discussion going on: https://github.com/WICG/ad-click-attribution/issues/27

I hope this becomes a highly-collaborative document with multiple editors. Please feel free to add additional use-cases (I'm confident this list is *not* comprehensive!). I'd love to add more columns to the table to cover additional browsers like Microsoft Edge, and Mozilla Firefox. I'd love to replace more of the "No Support" cells with something else (browser vendors, please feel free to update / correct these cells!)

Looking forward to discussing this document and iterating on it together with this group this week.

--Ben