Mint - offers a personal finance app for budgeting, planning, etc. -- and perhaps monetizes with affiliate links.
Hipmunk - meta searches multiple travel sites, provides ratings and reviews, assigns an overall experience metric, and supplies other actionable info for travelers.
Pinterest - allows discovery and sharing of content and other interaction (BTW, unless they recently restarted their affiliate-monetization scheme, they no longer are "just an affiliate". I have no idea though).
I'll grant you that at some level anything is "just" an x. I'll also grant you that the determination of value is frequently subjective (for instance, I never got the fanaticism around Pinterest).
But, there is some point at which the added functionality/feature set of a given thing is so thin that it is very difficult to see where any significant value is being added or that there is any uniqueness. Aggregating products from different retailers? That's been done in spades.
The other element, I think, is that HN has a different standard. Because its readership is very highly tech and startup oriented, people who show here generally have something that is at least somewhat more unique. So, I don't think it's overly harsh for a reader to comment that he/she doesn't see anything unique or particularly valuable in this offering. In fact, that's pretty good feedback. The affiliate world is brutal and if this is all they are bringing, then they are likely to find it extremely tough going.