I was having coffee the other day with a smart fellow who runs www.nationwidenetworking.com.au in Melbourne. He introduced me to an idea that had me thinking "fantastic" at the same time as "why haven't I thought of it before?!".
The idea is co-registration. That is, when someone is in "opt-in" mode and signing up for your website, when they've finished give them the option to check a box to sign up for one or two other related business newsletters at the same time (potentially with an incentive). This gives you the chance to either (a) charge for names you're collecting for someone else OR (b) do a reciprocal deal with another business that builds both of your databases at the same time.
And the "cost" for this great database building technique? Well, after a bit of tech time, pretty much zero.
See how smart this little "two for one" deal is? Who could you be working collectively with to get that database growing?