On the Internet, small is the new big.

Instagram is “a fast, beautiful and fun way to share your life with friends through a series of pictures.” And boy are they hot right now. In fact, Facebook tried to buy Instagram this past summer but the boys said no. If you’re curious why people love Instagram, here are two interviews I did recently with Instagram fanatics.

Path has emerged as one of the first mobile-only social networks and in January it reached over 2 million members. I’ve been loving Path (here’s why) for a while now and much prefer it to Facebook these days.

And then there’s Pinterest, describing itself as such, “Pinterest lets you organize and share all the beautiful things you find on the web.” It’s been kind of successful, being the fastest growing site of all time and all. Everyone at Engauge seems to be obsessed with it. Oh, and its not just for the ladies ;)

So the three hottest web properties today, Instagram, Path and Pinterest, are beginning to eat away at the big boys. Probably not enough to annoy them yet, but they soon will.

Why are these sites gaining traction? I have some thoughts…

They’re nichier. Yes, I realize there’s a good chance that nichier isn’t a word. If its not, and I’m too lazy to check, then it should be. These sites are all hyper-focused on one area. They aren’t trying to be everything to every one.

They’re more visual. I’m a huge believer that the killer differentiator for technology is the user experience.

They’re more exclusive.

They’re browsier.

And they’re coming at a time when the smaller, nichier social sites of the past have become massive, mainstream sites. Yes, we’ve seen this before.

Think about how Facebook started. There were already a few social networks out there (MySpace and Friendster), so what was different about Facebook? It had a simple design, but more importantly, it was a smaller network. Only for college kids. Every college kid at that time was on MySpace, along with the rest of the world. So when this smaller network popped up it became a place for more intimate conversations and personal connections.

The same can be said about Twitter when it first came out. It was fun because only a small, concentrated group of people were on it.

Now Facebook and Twitter are huge and these new guys are starting to dig away at their users. Both of these sites have “become” the Internet, making it almost impossible to extricate them from the web itself. People are once again looking for smaller, nichier experiences. And Instagram, Path and Pinterest are there to fill that need.