This story about people's HomePod leaving a ring on their table is kind of crazy. How did Apple, a company that’s been shipping home electronics since the beginning, ship something that can damage your furniture? If they did know this was possible, they should have addressed it. If they didn't know about it, that's even more concerning. I'm probably making a bigger deal out of this than I should, but I expect more from Apple.
I don't know how big (or small) of a problem this is but the pictures are damning. I've had mine on my wooden desk for a week, and there is no sign of a ring but I like this desk, and I don't want to damage it. If you are coaster shopping, you can go crazy with something like the Pad & Quill solution or you can just cut out a piece of firm cardboard, or use an existing coaster. Ultimately, I spent $5 on a cork plant coaster from Amazon that should do the job.