I posted this comment over on an article about “right or wrong” with webcomics at The Floating Lightbulb, but in the event that Bengo decides not to publish it for some reason, here it is again: It’s a bit naive to think that a content feed is inherently destructive to item sales. If you look at a site through an update feed, do you actually look at the news box or the store? With a content feed, news posts and store items and the like can be put right into the content feed - but with an update feed they generally do not.
Also, in my experience, update feed items are very easy to overlook when skimming. I do usually end up going to the site directly for comics in which are provided in the content feed, since they’re often too wide for my reader, but the content feed can include a lot more than just the comic.
For example, the content feed on my comic contains the comic, the news posts, some non-intrusive PW ads, and the comic’s transcription, if it’s available. Those are things that most people would never, ever see if they were to just look at the comic on the site. If you would like to help to prove or debunk my point, please post a comment on this news post indicating whether you saw the news post via the feed or via the site.