Monday through Wednesday in New York City TechCrunch is holding its Disrupt Battlefield competition in which hopeful founders and entrepreneurs submit their young, unseen start-up companies for the opportunity to try winning a $50,000 prize while launching in front of an all-star panel made up of innovators, angel investors, venture capitalists and tech influencers. Tuesday featured three Battlefields: Disrupting the Real World, Disrupting the Enterprise and Disrupting Streams and Collaborations. These start-ups made presentations in the Disrupting Streams and Collaborations category:

Madbrook Publishing unveiled its Everything Butt Art ^[1] children’s educational book and free iPad app that teaches step-by-step art in which every drawing begins with a child drawing the shape of a butt (not the cigarette kind, the sitting-on-it kind). The app allows kids or parents to save art to an online gallery and even add photos of regular art from school, both of which can be shared via social media platforms like Twitter.

We recently wrote about Kohort ^[2] because it was somehow able to get thousands of people ^[3] to sign up at its site even though the company’s purpose was unknown. Until now. Kohort says it’s a service that connects people who share a common interest, such as groups of mothers, alumni or sports groups. Kohort gives every group its own page with robust tools for organizers such as event listings, ticket sales and tiered dues. Kohort is free for groups with less than 15,000 members.

Meporter ^[4]is a location-based iPhone or iPod Touch app that lets you to write, photograph, and record video of your local news as it breaks then post it for the world to see. Readers will see a user’s location, can comment on stories, and check in as eyewitnesses. Meporter only allows reporters to post local news, and readers to post comments, if they are on location.

Tracks is a mobile app that lets people contribute to photo clusters, called Tracks, which are created on the fly. For instance, if you went on vacation with family or on a pub crawl with friends you could invite others with you to add photos to a Track. Everyone contributing to the Track can then view it the app and on the web. Tracks also can be printed a magazine format.

CatchFree ^[5]is a community-driven website that lets people discover and share the best free web apps and avoid those with hidden catches. CatchFree will refer users to a range of freemium apps and services at no cost, and for those services approved by CatchFree community members, the startup will collect fees from referrals.

CodeGuard ^[6], chosen by TechCrunch Disrupt attendees as the Startup Alley audience choice, also pitched its service. The company, which is targeting SMBs that don’t have significant IT resources, backs up web sites so that users can undo any changes to the site if they need to. Currently the service is free to sites that are smaller than 250MB. The company is offering 5,000 free accounts for its public beta. To sign up, go to CodeGuard.com and use the code “TCD” to create an account.

Read more about Everything Butt Art ^[7].
Read more about Kohort ^[8].
Read more about Meporter ^[9].
Read more about Tracks ^[10].
Read more about CatchFree ^[11].
Read more about CodeGuard ^[12].