Co-registration has been touted by many industry gurus as a great way to build email lists as well as a lead generation strategy. For those of you not familiar with co-registration, it is where your opt-in offer appears alongside or after the opt-in form of another Web site. The idea behind this is that since it's sometimes difficult and time consuming to get people to come to your Web site to opt-in, it is easier to syndicate your opt-in offer to other Web sites. I concur that co-registration advertising is a solid strategy, as I have firsthand knowledge of many advertisers building strong lists and generating hot leads. However, as the practice gains momentum, co-registration intermediaries have become secretive about their methods -- leaving many advertisers guessing where their data is coming from. The blind networks that co-registration intermediaries have created does in fact devalue the data they deliver and are a disservice to the publisher, advertiser and your typical "Joe Public." For advertisers, not knowing where their co-registration leads came from puts them at a disadvantage when trying to establish trust with potential customers. If they can't reference where they received a lead's name and address, it is often ignored or written off as spam -- putting the lead in a defensive position and making the advertiser look less trustworthy. In return, since leads often need to be reminded that they opted-in to an advertiser's offer, they are self-deprived of the information they were originally seeking when they click the spam button or consciously ignore the advertiser. But it's not just advertisers and prospects that get the brunt from a blind network. Sometimes the website publisher loses out in the co-registration process when the intermediary places contextually irrelevant advertising just to make a quota. This denigrates a user's experience. Given these scenarios, I can't understand why both advertisers and publishers continue to participate in a blind network -- and why the co-registration intermediary can't disclose to the publisher who the advertiser is, and vice versa. I understand that disclosure would be inefficient for a common banner network where the main goal is branding and the banner experience is more than a one-time phenomenon. But, co-registration's main goal is data collection and it is a one-time experience. Therefore there is no reason why non-disclosure from the intermediary should exist, and it needs to be treated differently. If you feel that you must participate in a blind co-registration network, please keep in mind the following to help ensure success: For advertisers: