Fototwics (free) is a photo sharing app that joins a crowded field with offerings from titans like Apple, Facebook and Instagram.
The difference is that Fototwics is not a filter or photo altering app, but just a way to share your photos privately or publicly. For public sharing you can add hashtags, and also use the tags to see photos that may appeal to you. Essentially, Fototwics is a photo blogging app that gives you some of the features of Apple's PhotoStream, and some of the photo sharing features of Instagram. The Fototwics designers were aiming for something different from Instagram though, as it dispenses with likes and dislikes and lets your photos be shared with groups or individuals who then re-share or "re-twic" the photo to others. Fototwic is trying to break open the closed sharing model of Apple and Instagram, and it seems to accomplish that.
Fototwic requires a free signup that generates a user name for you. As soon as you're signed up, you can post publicly or privately while you generate followers.
Photos can't be modified other than cropping and rotating, but there is nothing that stops you from posting a photo you have edited in another app, including Instagram of course. Your images can be shared via Facebook, Twitter, Instagram, Tumblr and Flickr with a single click. Other Fototwic users can leave comments on your pictures, and you can do likewise to other photos.
Using the app is simple. Take a picture from within the app or select one from the Photo Library. Both front and back iPhone cameras are supported. You decide whether you are going to share the picture privately or with the entire world, and you are on your way. There are no storage limits with the app, so you can share as much as you want.
For Fototwics to really work, the app is going to have to develop a large community of users. Looking at the public postings, it's clear that there is not a lot of activity yet. That may change, but until then the app is a still a nice way to share photos with friends or family. Help is built-in and you can block any user of the service.
Fototwics requires iOS 6 or later. It is not universal, but it is optimized for the iPhone 5.