I've recently started building a new list using JV Giveaways and in 2 weeks time this list was 323 subscribers. To start building a list this is the best and fastest way and you should know that your mailing list is your greatest and most profitable asset in your business online. That's how those big dudes make the big cash...no joke !
To build a list through giveaway events you sign up as contributor and spread your own specific invitation link on social networks. The more contributors (or members) sign up through your link, the faster you grow your list. When you have a few hundred subscribers you can start doing adswaps with list owners of similar sized lists or even bigger lists.
Here's a list of running and upcoming JV Giveaway Events that need contributors:
JV Giveaway Center
Try it !
Focus on building a list for a few weeks and you'll see the potential.
Andre