An article in today's PaidContent discusses an unusual move by the New York Post newspaper to not only impose forced site registration, but to ask for personal details including birth date, email address, zip code and income. Reportedly, the registration form was hurriedly removed after numerous complaints and highly negative press coverage from rival New York papers, although I encountered this very registration form just a few moments ago.

What is the New York Post thinking? Who knows, as the Post won't comment on its move to collect a lot of information (making registration much slower), and a lot of very personal information at that.

Even at this late date, publishers remain remarkably divided about the merits of forced registration. Publishers who derive the bulk of their online revenue from advertising generally don't want to lose even a single set of eyeballs against that advertising, and generally opt for no registration at all. That maximizes traffic, but at the expense of knowing much about their online audience.

Another group of publishers believe that, since they are providing valuable content to visitors, it's not unreasonable to ask visitors for some information in return.

Complicating the registration decision is the extreme variation in results when registration is implanted. We know publishers who have seen their site traffic drop by as much as 80% after requiring registration. We also know publishers that have only experienced a 20% drop. We know two publishers whose traffic dropped briefly and then actually began to increase over pre-registration levels. Of course, many of these numbers reflect the anarchic state of Web analytics, which at the moment make it hard to predict the true impact of forced registration.

Leaving aside the tricky question of whether or not to require site registration, here are the ground rules if you go the registration route: ask as few questions as possible (the longer the registration process takes, the more visitors you will lose) and make sure you can fully justify every question you ask. Hey, we're all in the data business, and it's a natural instinct to collect more data. But we've seen more than a few publishers who have taken a traffic hit as a consequence of forced registration, and literally never bothered to look at the data they collected. So don't succumb to data excess or you'll just end up with excess data. If you don't have a known and compelling use for the information, don't collect it.