Lots of things potentially have tremendous value. If Reddit were building a profile of you based on your clicks and votes, they could give you incredibly targeted advertising.
Clearly Google wants all its user data piped through G+, and developing separate signals for Reader wasn't worth their time. Notice also how they've done absolutely nothing with podcasts since discontinuing the side project that was Google Listen. Unlike iTunes, Google has no podcast directory whatsoever. My guess, they can't reliably index audio so they have no interest in the medium, despite its growing popularity.
Google is one of the few companies that can afford to not only "go where the puck is going" but indeed, influence where the puck is heading the in first place.
I think the reader and podcast stuff have far more to do with focusing on G+ as a "vision", to bolster shareholder view of "google needs to mature and produce a vision for the future", etc.
Someone will come up with a killer audio indexing, google will buy them, then suddenly 'get' in to audio, but they'll also have wasted a lot of time in terms of their own infrastructure surrounding audio/podcasts/etc, when in reality, it's comparatively few resources for them to be spending in the first place.
"Clearly Google wants all its user data piped through G+,"
Equally clearly, they're living in a fantasy world. G+ is a ghost town. I have ~150 people in my G+ circles (lots of friends and acquaintances signed up out of curiosity when it was new) and see maybe 2 new posts per day. My Facebook feed, which has roughly the same number of people, gets somewhere close to 100.
Clearly Google wants all its user data piped through G+, and developing separate signals for Reader wasn't worth their time. Notice also how they've done absolutely nothing with podcasts since discontinuing the side project that was Google Listen. Unlike iTunes, Google has no podcast directory whatsoever. My guess, they can't reliably index audio so they have no interest in the medium, despite its growing popularity.