> Why flirt with ambiguity? Just make it mandatory: It takes customers five seconds.

> Perhaps most important to dispel is the myth that asking people where they heard about you is going to destroy your signup conversion rate.

The problem with making it mandatory to answer this question isn't that you'll drive customers away, it's that customers will provide bogus data.

I rarely remember where I've heard about a product or service, so I am rarely even able to answer this question. If I can't skip it, I'll just click on whichever answer happens to be under my mouse cursor in order to get past it.