If you've taken a look at Facebook, Instagram, and Google+ lately, they all kind of look the same. The differences are subtle, so if you're wondering what you would like, I will try to explain:
• Facebook. If you've never done anything on the web other than looking at web places, Facebook is the best place to start. There may be thousands of social media sites out there, but this is the big one. People you know will be there, your family will be there. It's a place to post pictures of yourself at parties, the lunch you are about to eat, and other wonderfully trivial things that make being a human connected to other humans a joy. No pressure, just post a picture and write a short caption.
• Instagram. Instagram is for quick random photos. You can write a caption if you want to, but that's really not the point. If you see a picture of a sunset, and want to post the photo, use Instagram. With the app on your SmartPhone, nothing is easier. You can post on Instagram about as fast as you can take a photo.
• Google+. As a failed social media site, Google+ has evolved itself into a place of shared ideas and interests. It's not quite as light-hearted as Facebook, and it's very "caption-heavy". On Google+, you're more likely to see a long descriptions.
I hope this helps. Nothing else matters (sorry, Twitter!). And of course one isn't really better than the other, they're just different, and appeal to different people. Or they can all appeal to you as your moods change. Sometimes I just want to look at pictures of dogs!
By the way, if you read all of the way through this blog post, you would probably prefer Google+. If you looked at the picture of my dog, and read the first sentence, or skipped immediately to this last paragraph, you would probably prefer Facebook. If you didn't click on the link at all and just looked at the photo and smiled, you would like Instagram. They're all great places to be.