I resisted the siren call of Instagram as long as I could. Although I love taking pictures and showing them off, it was difficult to figure out why I would need to join the Instagram community. After all, there's Facebook and my blog -- surely that's enough self-promotion for any normal person.
Several of my knitting circle are on Instagram, and they have managed to convert me to the wonders of this program. I love that I can share what I am doing, in the moment. There's no finding time later to upload and describe, which is what's involved with a blog post. And, for now anyway, I don't have to edit and limit what I share since I only have a handful of followers who even know I'm on. So I can have fun and be me without censoring. (There are too many family and professional ties on Facebook to feel that same freedom.)
I have Instagram as an app on my iphone. I can take a picture from within the app, or use a photo from my phone's photo library. There are some really nice editing tools, including several filters as well as cropping and focus. You can let your photo speak for itself, or add a short note as you upload it. Others are free to "heart" your photo and/or add their own comments. You can follow people you know, which puts all of their photo posts in your updates. If you're bored, you can randomly view pictures other people have posted. I found a fellow tatter that way -- she's become a wonderful resource for tatting patterns.
I still feel that a lot of our online communities are just self-promotion rather than real friendship. But I'm willing to buy into that, if it allows me an outlet and an excuse to keep taking pretty pictures.