I shall just cover the mobile portion since, in my view, it's more relevant. Keep in mind this will be available on Android AND iOS. As with most big Google projects, it's invite only until it officially launches. Market link above lets you download the app for android, but it's useless unless google invited you. This app is going to cover alot of what I consider archaic nowadays. Like MMS. I hate MMS with a passion. I used to laugh at some early smartphones (like original iphone) for not handling mms. But now, I really could care less about MMS. The carriers compress the shit out of the photo and it just gives you a grainy mess. I only use it for the 1 or 2 friends of mine that still use a basic phone. I email some of my friends photos, but even then, I have some philistines that own a smartphone and don't sync their email with it, so I use imgur and send them the link to it. The messaging also works really good too. I used to be the middleman in organizing events even if I wasn't the person that created the event. Seeing as the facebook app is inconsistent across different platforms, handling events on that is pretty horrible. This looks like it works as a messaging chatroom. Google+ Project Page
It's probably the most common question right now. This is what I have been copying and pasting to all of my friends. "Select the people you want and drag them to a circle. You will see an invite prompt show up at the bottom. Confirm it and email will be sent. If you don't confirm it, you will have to recreate the circle to have the prompt show again." To compound to this problem, it seems that google has stopped allowing invites now. I think they hit their threshold. They might be opening it up again soon.
It's your data, your relationships, your identity. Lol just that last part is pretty scary... I don't know what your talking about here, it sounds like voluntary assimilation to the droid hive :x
It actually has nothing to do with Android. Notice I mentioned the app will be available on iOS too. The app portion is just the mobile part of it. Google+ is Google's take on social networking (facebook). The Google+ Project page link is given at the bottom of the op if you want to see more.
Seems like this is really taking off. It might have 20M users by the weekend. Could this replace facebook in the long run? http://www.pcmag.com/article2/0,2817,2388371,00.asp
To put cmdrmonkey's post in perspective, Google+ was only open fully for the last few days. From June 29th until about this last Friday or Saturday, invites were only open for x amount of people. Once they hit that limit, they closed it. So basically for a little over a week, invites were only open for about 15-30min each day. The fact that they're reaching this amount of users is pretty impressive.
So five months have come by and Google has made a ton of improvements to Google+ although it's not even close to being as widely used as facebook or twitter. It's not really comparable to facebook though.. more of twitter with facebook features. I'm not sure how many of you guys actually use it but the android app is useful for many reasons even if you don't use the actual service itself. PHOTO BACKUP - Turn on instant upload and your photo/video collection on your phone will automatically be uploaded to google+. They won't be published unless you choose to do so. Also any future photos/videos you take will also be uploaded automatically. VIDEO CONFERENCING - Today's update of the app added the hangouts ability to Messenger (aka Huddle). No more need for a 3rd party app. Also this looks like what google was looking to do in the long run rather than adding the video chat ability in googletalk for all phones other than the Nexus S (http://forum.pcvsconsoles.com/viewtopic.php?id=460). Will be interesting to see what other plans Google has with Google+ for android.