Well, I don't do it much anymore, but in the past I've wasted innumerable hours arguing online about religion, or in debates that are irrevocably tainted by religion (like abortion, evolution/intelligent design, etc.). So that's a negative result. But I have been an atheist for decades, so there's no need to respect any religious edicts.
I've long gotten the sense that hackers have a better-than-average grasp of rationality, which means fewer of them ascribe to any major religion (though being more vaguely "spiritual", meditating, etc. isn't ruled out). There's just such a huge amount of obvious nonsense wrapped up in major religions that if you have the habit of taking things apart to see how they work, you'll eventually apply that to this thing that your parents told you should be a central part of your life, and religion doesn't stand up well to analysis that doesn't assume its truth.
Hackers still usually have families, though -- sometimes families who are very dedicated to religion -- which means there are quite a lot who still go through the motions (at least when visiting home, for example) just so their Grandmother doesn't have a heart-attack because she thinks her grandchild is going to hell.
I personally just sort my way through the conflicts as patiently as possible (I have a family that's full of pretty serious Catholics), because I can't stomach faking it, and generally I'm not harassed about it, much.
For religious hackers -- I suspect their religion's requirements aren't too heavy. Generally we're more productive when we take breaks now and then, so feeling obligated to stop and think of something else for a bit is probably a good thing.
Whether they make a difference in decisions otherwise -- possibly, but probably not as you might think. I grew up in a wealthy area, and Christmas mass meant a parking lot full of expensive cars and pews full of fur coats. If they actually listened to the sermons, they'd hear they had the same chance to pass into heaven as a camel through a needle's eye, but that didn't affect how they used their money as far as I could see.
On the contrary, among people who are genuinely interested in making the world a better place, I suspect an atheist would be more likely to carefully analyze complicated situations before deciding what path might lead to better results, and test the outcomes... whereas anyone with strong religious beliefs would believe they already knew what was required. Think of how many AIDS cases could have been avoided if so many Christian missionaries weren't opposed to birth control....
I've long hoped that greater interconnectedness will lead to less belief in the supernatural globally, but that hasn't been the case so far -- I don't have the study link, but from what I've read people are more likely to seek out like-minded sites/people, to reinforce their beliefs, not sample widely to find out if other approaches might be more valid.
Create a startup targeted at religious people? Not seriously. I've toyed with the idea of creating sites to explain gently & non-aggressively what atheism is and why some people choose to be non-believers, or to offer support to people trapped in highly-religious communities and families who have lost their faith -- but idea #1 would likely be fairly useless (see previous paragraph), and some sites already exist for idea #2.