While that may be considered evidence of potential customers switching browsers just to use 4ormat.com, it may also be considered evidence that potential customers using IE are very much put off by being told to use another browser.

Just running the numbers on a back of envelop:

The company was founded in 2008.

Not supporting IE has saved $25,000 per year.

12 months x $7 per month = $84 per user.

330 lost users = $25,000 +/- per year

10,000 responses to the call for action * 4% using I.E. = 400 visitors who are much more unlikely to use 4ormat.com because the call to action doesn't work. Their negative experience is much more likely to lead to negative network effects than positive ones.

Even worse the lost revenue scales as the customer base grows, but the work to support IE is roughly fixed and is relatively modest.

$25,000 is 4% of $625,000 a year. Above that, the company is losing money (on the back of an envelop). With four founders, one would expect that 4ormat.com's revenue is projected to exceed that or has already.