It turns out that I was mistaken the other day when I mentioned that I had spotted ads in my PubSub feed. While there are ads in the feed, they aren’t from PubSub, they are part of the original RSS feed that PubSub had picked up on, in this case it was from Freshmeat.
This raises an interesting issue for PubSub, if they decide to show ads in their feeds (why not, most everyone else will start doing it), how am I as a regular user supposed to be to tell the difference between an ad placed by them and one that was part of the original data (in this case an RSS entry)? They could certainly include some formatting that would make it obvious, but then that would also allow feed readers to also easily distinguish the ad from the data and hide the ad. Just more to think about when it comes to ads in feeds.