Your site visitors care about one thing - how you can help them get what they want.  They don't want to read all kinds of long, boring prose about how great your company is or it's history, nor do they want to have to give you their name and email just to be able to view more information about your products or services.  Your visitors want a solution to their problem - whether they're looking to buy a product online, or whether they just want a good laugh from your joke of the day.  Don't scare them away by demanding information from them before they're ready to provide it to help themselves.

I thought the following pretty much went the way of the 90's, but recently I was researching a product and ending up on a major company's website, only to find that I couldn't even reach the product information page without encountering "let us know who your are!"  Well....NO!  I immediately left the site and returned to Google, and the company lost a sale to another site.  There are too many competitors out there for you to alienate potential customers by demanding information from them before you've earned it.

Site owners are learning that gradual engagement is the best way to not only increase user signups, but also to end up with users who are more engaged over the long run.  Gradual engagement allows site visitors to sample a site's service before having to register; by allowing visitors to see for themselves why your site is valuable to them, when they decide to register they'll be more likely to actually use the service.  An example of this is with bit.ly, a site that allows you to shorten url's for easier sharing. All you have to do to shorten a url is visit their site, paste in the url, and click "shorten."  Once you're using bit.ly and determine their service is of value to you, you can choose - or not - to create an account; by having an account you can track clicks, see how many times a link has been shared, etc.

How can you gradually engage your site visitors so they'll be more likely to want to share their contact information with you or register an account?  An example with email newsletters: allow visitors to view past issues, allow visitors to subscribe to an RSS feed without submitting any of their information - and finally allow them to actually subscribe to receive the newsletter in their inbox.  If you provide an online service, try to offer a stripped-down version that doesn't require registration; what types of features can be made available that don't require being tied to a user account?  When a user does choose to register, limit the number of fields required to the absolute minimum (usually name & email) because many users are turned off by long forms and will just leave.

Moral:  give users a reason to want to be a part of your site and then make it easy to do so.