I must agree with Mark.
His two reasons are well positioned, and besides, he's not discussing digital imaging directly. He's simply offering APUG readers a membership deal to an organization that discusses digital imaging directly. And, according to him, may expand their efforts into the analog regime.
Don't we here essentially do the same every time we recommend someone to go on over and join the hybrid photo site? Offer them a membership to an organization that discusses digital directly, but without us discussing it?
I see no mention of test results, longevity estimates, comparisons to analog, or digital product recommendations and/or endorsements. Only an effort to further his business a bit, which is, after all, what these sponser forums are all about.
No harm, no foul?