Editor’s Note: This is a guest post by Tyler Rooney, a co-founder of online portfolio startup, 4ormat.

It’s not every day that you start a business and quickly decide to say “no” to 70 percent of your potential customers. In retrospect, this turned out to be 4ormat’s secret weapon.

At 4ormat, our goal is to provide an easy way for creative professionals to create and manage an online portfolio website. Although the portfolio itself looks great in all browsers, to this day, the portfolio building interface does not support Internet Explorer. And we don’t just mean IE6 or even IE7. We mean every version of Internet Explorer.

This might seem drastic, but consider this: when we started 4ormat in 2008, IE had almost 70% market share and IE6 was still used by one-in-four desktops. Chrome, for example, had only been out for 2 months. To call it drastic would be an understatement.

We were bootstrapping 4ormat in our spare time while consulting full-time. Every hour we spent on development was another hour before we could get the product in front of customers. We didn’t support IE6 from the getgo, but rejecting the 45% of people who used IE7 (and the newly released IE8) seemed like something that would cripple the business. The goal of 4ormat was to make building and updating a portfolio as simple as possible. To do that we wanted to leverage every possible bit of modern browser technology.

Within a week it was painfully obvious that for every great idea we came up with we had to create equally terrible hacks to support IE7 or even IE8. Supporting variants of IE can easily increase design work by 30% to 100%, but complex features can easily double (or even triple) development time. It doesn’t take many developer salaries before this “IE tax” can cost you well over $100,000. But the money you lose as a start-up pales in comparison to the time and energy lost.

In the early days, you’re looking for quick wins to validate your ideas and to start building momentum. Nothing kills this like discovering that the feature you worked so hard to build completely falls apart in IE. Nothing upends developer velocity like spending days in a virtual machine painfully debugging an issue with Internet Explorer’s woeful dev tools. We decided that in order to get a viable product out the door we would simply not support IE. It was possibly the best decision 4ormat ever made.

The change was simple. Our signup form now tells IE users where they can download Chrome, Safari, or Firefox. To date, almost three years after launching 4ormat, not a single person has ever contacted us requesting support for Internet Explorer.

We realize that there are lots of businesses where supporting IE is a hard requirement, but if you’re a lean start-up where IE support does not matter to your customers then dropping it has some major competitive advantages:

Huge productivity gains. Everyone on your team can focus on what really matters. Developers can develop, designers can design. And in the early days you don’t have a dedicated customer support person; troubleshooting remote users can be incredibly time consuming.

Shorter release cycles. Supporting IE is a signiﬁcant portion of development and design. Remove it and turnaround time for new features goes down. This is huge for new companies looking to validate their ideas.

More manageable bugs. Nothing has more potential to ruin your day like a bug report that contains “only in IE”. IE bugs tend to have an unquantiﬁable X-factor. Fixes are just as likely to take 5 minutes as 5 days, which can make sprint planning that much more difﬁcult.

Happier and more satisﬁed employees. People simply enjoy their job more and know they accomplished something real at the end of the day. How would you feel if you were unburdened by legacy web development issues and could always use the latest and greatest JavaScript libraries and CSS features?

Recruitment secret weapon. It warms our hearts to see the look of incredulous joy on the face of a job candidate when we assure them “You heard right, we really don’t support IE.” If this sounds interesting, check out our open positions.

So, the take-away: don’t be afraid to make decisions on behalf of your customer to simplify your life and get a product to market sooner. It’s important to test your assumptions, especially early in the life of your business. In our case, we assumed that nobody in their right mind would want to build a website with IE. Because of that, we saved ourselves countless headaches, a lot of money, and a ton of time. More importantly, we’re happier, better understand our target customer, and spend more of our time focusing on real customer problems.