Writing applications for cloud environments is a different affair that writing for in-house hosting. At the All About the Cloud summit in San Francisco this week, the focus was on what changes developers need to make to their applications to enable their optimal use in the cloud. Perhaps the most interesting revelation offered during the event was that of the direct correlation between billing and the quality of source code.

Treb Ryan, CEO and founder of OpSource, said in a keynote talk that cloud hosting offers “the best margins I have seen in the hosting business.” He added that Amazon has largely played down the profitability of cloud hosting, and he suggested they have done so to scare off potential competition. OpSource has been offering hosting for software-as-a-service applications for more than five years and has relatively recently entered the cloud hosting business.

Ryan said that applications hosted in the cloud are under a performance microscope. If they send too many requests to the database, that will be reflected by a higher bill at the end of the month. He said that developers writing applications for deployment in the cloud need to realize that “bad code costs me twice as much as good code. I can cut my op costs in half” by optimizing the code.

Thus, said Ryan, developers can see a direct correlation between the code they’ve worked on all month and the reduction in their cloud hosting bill. That’s something developers haven’t really been able to do since the days of mainframes and time-sharing.

Elsewhere at the All About the Cloud summit, attendees and speakers discussed the remaining problems of the cloud. Integrating cloud applications with on-site systems was one of the first and most painful points discussed.

Paul Daugherty, chief technology architect at Accenture, said, “We are at an inflection point where integration becomes more critical. Increasingly we’re seeing a big increase in data sources used. Initially integration was about two different applications, but now it’s getting into the 10s and 20s.

“There was an interesting piece of research Gartner did: They looked at companies using SaaS applications. One of the less obvious data points out of their sample respondents was that 14% or 15% adopted SaaS, then reversed back out onto on-premise. The No. 1 reason for that is cost of integration, and cost required was too great.”

Another remaining cloud issue is security, said Ryan. “We’re still addressing security. The idea that the vast majority of cloud environments have the same user name and password for all users is ridiculous.”

He added that most cloud providers do not currently offer a way to tie multiple accounts together, and thus whole companies sometimes use the same login and password for their cloud environments. Instead, Ryan would prefer accounts that could be used by each user, but could also be tied together for collaboration on the same virtual machines within the cloud.