For the uninitiated, here's a quick definition. A squeeze page is a webpage that, when the visitor "lands" on it, he is asked to opt-in to some type of list in order to proceed further. On some squeeze pages, your only options are to opt-in or leave. On others, you are given a method to continue exploring the site without opting in. Purist would argue that the second type isn't a real squeeze page.
The rationale behind using a squeeze page is that most Internet marketers realize that the vast majority of visitor will not buy from a site on the first visit. So, these marketers make list building their top priority. If they can just collect the email address, along with permission to follow-up, then they'll get other opportunities to make the sale later.
A squeeze page, generally, has some enticing bullets on it, and does a thorough job of describing what you'll be able to access after you enter your data. The enticing offer on the squeeze page, that has the visitor salivating to get at what's behind that "door," is essential.
The most effective squeeze pages that I've seen used enticing emails to drive traffic to the sites. These emails were either emailed by joint venture partners, or by the product owner who was introducing a new product.
That email that drove traffic to the squeeze page, sent them there already READY to sign up. That email, if it did its job, thoroughly described what was waiting on the site, and so the squeeze page was only a slight inconvenience. It was not enough of an inconvenience to be noticeably objectionable to those who were already thoroughly sold on the product concept.
The enticing email that does the pre-sell is a step many less- savvy marketers skip. Because their visitors aren't pre-sold, their conversion rates are much lower than they would otherwise be.
Squeeze pages often experience "leakage" because many visitors know how to view the page's html source code, and locate the url of the follow-on webpage. So they can just enter that url to access what's behind the door.
A good way to prevent this type of leakage (if you want to) is to encrypt the url for that follow-on webpage. Another way to do this is to EMAIL what was promised on the squeeze page. So, if the visitor doesn't provide an email address (or provides a bogus email address) they don't get to enjoy what was promised on the squeeze page.
On the page above, notice that if you try to circumvent the squeeze page, you CANNOT just access the information. Instead, you are simply given another chance to opt-in. This is a brilliant implementation of a squeeze page.