It is a model which allows people to try before they buy, which also expands the audience and allows the game to spread. It is a good thing when implemented well.
It would easily be sufficed with a "free app" and "paid app". Apple just doesn't make this seamless. Consequently, the "freemium" model is born through in-app "upgrades".
As someone who hasn't bought a single in-app purchase (I might if Carcasonne add expansions), are these transferrable across devices like the apps are?
Yes, iOS in-app purchases are transferrable across devices that are linked to the same app store account. It is a somewhat strange experience when you do it the first time because you are basically expected to "buy" the item on the additional device and then at the last moment the system determines that you already paid for it and provides it for free -- I had visions of getting a bill for multiple in-app purchases of the same item but in the end it all worked out.
For this reason (and for clean installs) there's an option in the API for "restore purchases". Applications should provide this option in addition to "buy".
Another benefit of it is that it restores all in-app purchases for this app. Very helpful in case the application provides more than one purchase product.
It probably does, but 50 plusses aren't very impressive. You'd have to buy thousands of them in order to appear viable. And even then, most people who are able to recognize a high "plus" ranking would probably be sophisticated enough to recognize a spam site instantly anyway. This kind of reminds me of those weird sites with a button on them displaying 3 million likes on Facebook and when you look at the actual source code, it turns out they embedded the widget with "example.com" as their site address.
Fifty ClickMob accounts on non-social sites are worth a lot more, for a short time you could totally dominate sites like HN, Slashdot and Reddit. But Google+ accounts that are not connected to relevant people, I just don't see the value...
It could also be or become a ranking/search quality signal in aggregate.
Google may also show aggregate +1's in their search results in the future (so social proof right in the search results):
>>And even if none of your friends are baristas or caffeine addicts, we may still show you how many people across the web have +1’d your local coffee shop.
