Even though it has just been launched on the Apple platform only a couple of weeks ago, the Google+ app has created a lot of friends, being 10 million in the last 3 weeks, and even more enemies due to some limitations found on having it used on the rest of other Apple devices aside from the iPhone. One of such concerns is its limited support to devices. The iPod Touch and the iPad cannot download it and have it working.
In addition, if you have been successful on the download, maybe since you have an iPhone 3, 3GS, or an iPhone 4, you will not be able to update your profile just because you will not be able to. It will never work. You will not be able to share some pics, a post, or even a link using the app. With problems like this to begin with, looks like Google has to go quite a long way before Apple users give that +1 to this Google app.
Source: Unwired View