It seems that there is a tendency among marketers and other folks capturing information online to want to maximize the “effectiveness” of their form interaction by asking for as much information as possible. I’m sure that the thinking is along the lines of “Why simply ask a visitor for their email address in order to sign them up for an email service? They’re filling out the form, let’s also ask them for their name. Oh, and their industry so that we can target them in future emails. Oh, and this, and that…”
Eventually you end up with a form that has 15 different fields and a horrible conversion rate.
If I’m buying an ebook, why should I need to provide a shipping address? Nothing is getting shipped to me!
If I’m putting in a credit card number, why should I have to select my card type? It can be easily discovered via the credit card number!
If I’m signing up for an email newsletter, why should I have to provide my name? All you need in order to send me an email is my email address.
The goal shouldn’t be to collect as much information as you can – the goal should be to collect as little information as you can.
Another way to think about it is to collect as much information as you must. What is the absolute minimum amount of information that you must collect from a visitor to get them to the next stage of a process. Once you know that, just make a form that collects that much information.