Steve Blank likes to say that all startups learn from failure. At StartFast, a big part of the process is to define a business hypothesis, test that hypothesis and learn from the results. A failed hypothesis gives you the data and knowledge to make a better hypothesis and move forward. By it"s nature, StartFast accelerates that process, increasing the probability that a startup will find success before they run out of time and money. By the time Demo Day rolls around, these teams will have formed, tested and iterated on so many hypotheses, so many times that they will truly be ready to scale and be financed.

Another effect of the venture accelerator model is to increase the level of stress on the startup teams. Working long days on tight deadlines with so much riding on the outcomes, the founders naturally get a little frayed around the edges. In some cases, the stress causes a fracture - a team member realizes that they aren"t cut out for the life of a high-growth startup co-founder. There"s no doubt that this is traumatic, but better to test the team"s mettle and find issues now rather than later. Week Six presented a fair share of "team dynamics" as it is euphemistically called (AKA "cofounder issues"). StartFast mentor and TechStars alum Aaron Foss visited and shared war stories with the teams letting them know that their trials and tribulations are not unique. Nietzsche (and a huge number of lazy pop lyricists) said, "What doesn"t kill me makes me stronger" and that"s certainly evident in all the StartFast teams.

While dealing with team dynamics, these eight startups are also accelerating user acquisition, refining business models and testing out marketing approaches. Mozzo"s goal this week was to double to the number of users from the previous week while pursuing a controlled eMail marketing campaign. They exceeded this goal and in the process, gained a better understanding of the variables at play. Mozzo will launch other campaigns this week including LinkedIn, Facebook and reaching out to small-to-medium size businesses that are Google Apps users. Request an invite for MozzoMail here.

Cayotech continued driving strong downloads of GuardMyAngel on the Android platform, published two press releases, and is in the final stage of discussion with University of Rochester to include their flyer as part of the orientation material for incoming students. Cayotech is also experimenting with ad campaigns via Facebook, AdMob, AppBrain and others which are initially showing about $0.25 per customer acquisition. The team is sprinting to get their iPhone version out next week. Get the Android version .

PadProof has added over 500 photographers to date and is in the process of optimizing their event upload function to drive additional revenues.  The big photo labs that partner with PadProof can reach hundreds of thousands of photographers and the PadProof team is hoping to sign up over 5,000 photographers and 60,000 end-users by Demo Day. Download PadProof here.

Tivity applied growth hacking tips from StartFast Mentor Phil Kaplan and had a 55.6% increase in customer requests while StreamSpec continued partnering with new ad networks and web publishers.

RevoPT signed up more clinics and stream-lined their product work flow based on customer feedback. BitePal closed deals with more restaurants as StartFast HackStars Ben Gelb and Elliott Regan worked into the wee hours to release the beta product. Canvita continued to get validation, direction and sign-ups from mentors and others while also actively recruiting additional resources.

Also this week, StartFast sponsor Bousquet Holstein held office hours, assisting the teams with legal questions and issues. StartFast mentor Michael Geer shared with us the inside story on how mobile app Badoo grew quickly to 150 million users and StartFast mentor Martin Perry met with all the teams on site. We also had a Skype redux with StartFast mentor Jonathan Matus who runs hacker development for Facebook Mobile.