YC Demo Day Session 1: PlanGrid, Medigram, Zillabyte, HireArt, Flutter, Givespark, Popset, SendHub, Screenleap, Coderwall, LVL6

We’re here live at the Computer History Museum in Mountain View, Calif., where top early-stage fund Y Combinator is kicking off its biggest demo day yet — 66 companies are in this Winter 2012 class, and all of them are presenting (although not all of them are ready for publicity, so some are presenting their apps on an “off the record” basis.) Almost all of them are in the process of raising money.

The day is divided up into five sessions. We’ll be doing a post on each session. Here’s the first set of on-the-record YC Winter 2012 startups.

PlanGrid: The company offers an iPad interface for construction blueprints. It allows the construction industry to get rid of reams of paper and instead keep up to date on the latest changes to projects via their devices.

Since launching at the beginning of the month — see our in-depth coverage from then — the company says its client base is showing hockey-stick growth. This is already driving new revenue.

Medigram: Doctors can’t use texts because of HIPAA federal guidelines passed in 1996. The resulting poor communication has resulted in approximately $10 billion in losses — not to mention the illnesses and deaths.

The solution is a HIPAA-compliant group messaging app, that only requires a simple download to get started using. It’s already live at three hospitals at Stanford and in Palo Alto, Calif. Future plans go far beyond chat — lab reports, medical records, etc.

Zillabyte: Styling itself the “Palantir for salespeople,” this company tries to identify key new leads scattered around the web. Users come to its site, provide a description of their ideal customers, then the site uses a combination of human teams, machine learning and big data analysis to identify prospects across the web.

HireArt: Instead of asking applicants to talk about their experience, HireArt has them actually perform a series of tasks. As we covered earlier this month, this means that if an interview candidate claims to be an expert in Excel, an employer on HireArt might ask them to create an Excel model using a dataset they provide, then have them upload the completed file. Another employer may instead want to hear a creative’s pitch for a new product. It has helped hiring in hundreds of positions already, it’s seeing 40% growth and a 100% fill rate since launching in mid-December. Clients include Warby Parker, AirBnB, 1800 flowers, and Autodesk.

Flutter: An app for Mac that lets you control the play function on Spotify or iTunes by simply waving at your computer, the company has an even more interesting long-term vision. It wants to use gestures along with our voices to tell our machines what to do, as we covered yesterday, rather than pressing buttons or clicking a mouse. The app already has 15,000 downloads and has recorded more than half a million gestures from users.

Givespark: An app that lets celebrities launch fundraisers for their fans to participate in online. The idea is that lots of celebrities are on Twitter, and they often use that platform to highlight philanthropic causes about which they’re passionate. So the company lets them turn that awareness raising into actual money for the cause. And it’s already started working: A celebrity recently used Givespark to launch a campaign benefiting a bone marrow foundation, and raised $87,000 in two weeks.

Popset: An iPhone app that lets people passively upload pictures taken with their mobile phones to group albums. Yes, mobile photo sharing is a crowded space, but Popset says it is tackling a major problem that still remains: When people are at an event together, they still end up uploading their photos from that event to their own respective individual albums. Popset says it is already very popular with teenagers, and has been growing its user base on average of 20 percent every week since its launch.

SendHub: A group messaging service that spans email, SMS and other platforms, the company is now sending 120,000 messages per month, up from 6,000 at the start of the year. Customers include Stocktwits, the Republican party of Florida, and Teach For America. Future plans include integrating more communication platforms. Check out our previous coverage here and here.

Screenleap: It wants to “make screen sharing sexy in the same way that Dropbox made file sharing sexy.” The site lets people share their screens with others in one step, without needing to download any special software — viewers just need to follow the link sent by the screen sharer. The current status quo for screen sharing is Cisco WebEx, which Screenleap says requires a 15-step process to share a screen. In the six weeks since Screenleap launched to the public, its users have grown by 37 percent every week, and the average Screenleap session is over 22 minutes long.

Coderwall: A “credential repository for the hacker community,” Coderwall is a site where programmers quantify their skills and achievements by accumulating badges, rather than in the the typical resume format. The reason the tech recruitment industry is so bloated right now is because everyone wants to hire coders, but the best and most talented programmers aren’t actively looking for work or participating in sites such as LinkedIn. Coderwall purportedly is a fun community that programmers want to be a part of, so it can also eventually be a very attractive place for companies to look for new employees.

Lvl6: A mobile social game developer that has come up with an equation that it says “guarantees that our games will engaging, monetizable and huge hits.” It has some evidence of this. Its first game, Mercenary Inc, reached the top ten of all app stores and gained more than 250,000 new users in one week. Its engine lets it develop high-quality titles in a fraction of the time that competitors take.

Additional blogging by Eric Eldon

Read more Y Combinator Demo Day coverage and check out all 39 startups who presented publicly: