I just closed and re-launched the Steam client on my Deck in Desktop Mode and got something I've never seen before: a pop up window (or more properly a pop under, since it immediately moved to behind the main client window) notifying me about a franchise sale. I do not own any games from that franchise and I don't believe I've ever even purchased anything from that publisher. Checking the Store front page I found another ad for the franchise sale, and clicking on it took me to a page that told me in small print "This third-party event is presented by <publisher>".

In other words, it appears to me that Steam is now offering third party publishers the ability to force pop up ads when the Steam client is opened. And having looked through the client settings, I don't see anything that looks like a relevant control to turn them off.

Does anyone know if this is new (as opposed to me just somehow never seeing it before)? Is there any way to turn this "feature" off? I think this is even more annoying than the "What's New" ad shelf right at the top of the Library page, in part because at least that thing can be disabled by manually editing a CSS file.

And please, I'd rather not get into a discussion of the merits of these things, or even whether they qualify as ads. If you like them, good for you. I'm not suggesting they should be eliminated. But some of us don't like them, and us turning them off doesn't adversely affect you in any way.