I think Brian is pointing in the right direction, when he talks about offering something free on the site that has real value to the target audience. If it’s not a white paper, maybe a really well-designed decision tree that people can print out and have by their desk, or some other PDF that is the kind of thing people would want to save and keep handy.

Even something goofy, like a mock-up of a business card template that automatically generates uber-cool job titles, or something, could be a draw, with the right audience.

Another option is some sort of give-away for 2-3 new subscribers to be chosen at random.

Just some thoughts…