On why I think you are wrong:
Search Plus Your World just might possibly remedy a flaw that I've always found really annoying about regular Google search.
Example: When I search Google for "Live Music Ann Arbor MI", the A-G results I get are, in order:
A) The Ark, a music venue
B) The Michigan Theater Foundation, a popular arts venue that does mostly films with a smattering of live concerts
C) Blue Karaoke, a Karaoke bar on Liberty that is B.Y.O.
D) DJ Jace, a broken link presumably for a DJ...or former DJ
E) Sound Investment (?)
F) Mike Green and Associates
G) Paul Dooley, composer
So what's the problem?
I know a bit about the Live music scene in Ann Arbor, and anyone else who does will tell you that The Blind Pig is arguably the most significant Live Music Venue in Southeastern Michigan, let alone Ann Arbor. Kurt Cobain said it was his favorite place to play, anywhere. Yet when it comes to Google search results, it's at the bottom of the page. To say nothing of, I've never even heard of D-G, but they certainly aren't Live Music establishments.
Why? Probably because the Blind Pig doesn't give a squat about SEO, and neither do most of the other venues where you actually might see live music occasionally.
Now, with +1's being figured into search results, hopefully over time, people can indicate where they actually go for Live Music, or whatever else someone might be searching for. It's easy to see the potential for how this can improve the quality of the results you get.
P.S. Sorry to post this here, but since I won't comment on a Mashable page, and you didn't bother to share your article here, I guess this will work.