For many people, the iPhone camera -- always in your pocket -- is fast replacing digital cameras. And with the help of a bunch of applications, the pictures can look even better than typical photos.
The latest such app to get a lot of buzz is called Instagram. The app offers a dozen filters that transform photos to make them look old-fashioned or black-and-white or to adjust light and shadows.
Instagram is also a mobile social network with dreams of becoming the Twitter for photographs. Instead of following people's 140-character thoughts, Instagram users can follow their photo stream and get a glimpse of what they ate for lunch and the view from their office.
"You see the world through your friends' eyes, as it happens," said Kevin Systrom, a former Google employee who co-founded Instagram with Mike Krieger, formerly at Meebo.
The original photo.
Instagram also plans to introduce a Web site soon. Building a mobile app before a Web site would have been a foreign concept just a few years ago, but Instagram's founders say that communicating in quick snippets with a phone, on the go, is a new form of communication.
Of course, that sounds a lot like Twitter, and Twitter also lets people upload and view photos. Mr. Systrom said that Twitter has paved the way for simple communication, and Instagram is different because it is focused on photos, not text.
Other apps offer something similar, by transforming photographs, offering a way to share them or both. They include Hipstamatic, DailyBooth and Picplz, which we have written about.
The founders say that Instagram will distinguish itself by the strength of the community of people who use it. Since the app became available about a week ago, almost 200,000 people have become registered users and they are posting a photo every second.
During that week, Instagram has been overwhelmed with traffic and the service has buckled. The founders spent a night moving the whole operation from the single server they had rented to Amazon Web Services, which lets the service handle more traffic.
Instagram users can add location information to photos, and the people who follow them can comment on them and record that they like them. Users can also publish their photos to Twitter, Facebook, Flickr and, soon, Tumblr.
The app is free now but Instagram plans to eventually charge a dollar or so for extra filters. Instagram's founders, who have raised $500,000 from Andreessen Horowitz, a top venture capital firm, say they have plans to build a bigger business than selling filters.
"Filters are not the billion-dollar business," Mr. Systrom said. "It's photography. The next network is people interested in sharing life visually."