Google+ is a lot like Facebook, but different all at the same time. Instead of Groups you have Circles. Instead of a News Feed, you have a Stream. You have Albums, but you also have a Scrapbook. Instead of the "Like" button, you have a +1 button. You can also chat with your fellow gmailers like you would if you were in Gmail, but it's kind of like you were on Facebook chat.
While there are similarities, the differences are apparent. For example, all of your +1's are available for you to find at a later date. They are put into a folder, if you will, so you can access them if you choose. I've been seeing Google's +1 button showing up in various places, but I never really understood what it was for. It's only a matter of time before the +1 shows up every time right next to the "Like" or "Recommend" FB button under the heading of an article for you to share with your Google+ peeps.
Sparks. These are supposed to be things that interest you. Do you like fashion? Add it to your Sparks list and receive article and video updates about fashion related things. The more specific you are, the better your results will be. Then you can share them with specific people in your circles when you find something really exciting that must be shared.
Google+ also links with your Picasa account. Don't worry. I'm pretty sure your privacy settings are still in effect. I'm not sure if Google+ will be able to link to your Facebook account or not, but it would be nice to be able to transfer over albums from FB to Google+.
Hangouts are also a part of Google+. The idea I'm getting from it is that you get to go back to the way things used to be when you were younger. Remember when you got to see your friends everyday just by chance? Remember when you used to eat lunch together or just walk by the upper quad and a group of your friends had just randomly convened? That's the idea. You let your people know you are "hanging out" and then you can video chat with them and others all at the same time. It certainly doesn't make things like they used to be, but it is a nice thought that you could all get together if everyone is scattered throughout the states.
Here is a screenshot of what your profile would look like...click on the screenshot to view it larger.
I can't say for sure if Google+ is the next big thing, but it certainly is doing some things right. I have multiple Gmail accounts that I switch between, but I can still access Google+ with a click of a the Krista+ button at the top left of my Gmail account. Click here if you want to learn more. If you want an invite...let me know! I'll see if I can work some magic.