Traffic Sources and Traffic Ideas
Plenty of Fish - ads.pof.com
Facebook - https://www.facebook.com/advertising
Twitter - https://ads.twitter.com/
Youtube - https://www.youtube.com/yt/advertise/
Note: You can also simply create your own youtube videos and upload them, with your opt-in page link embedded in the video, or below in the description. Try producing several of these for best results.
SiteScout - SiteScout (formerly AdBrite) - You can buy a lot of traffic here. Great place to start.
BuySellAds - http://www.BuySellAds.com - Paid traffic from a ton of different publishers. Excellent site to get started with.
Google PPC - Google AdWords | Google (PPC) Pay-Per-Click Online Advertising - Paid traffic from one of the biggest sources on the internet. Put your link to your domain where there is your opt-in page for List building.
Bing / Yahoo Search - Explore Bing Ads resources and advertising solutions- 2nd tier PPC network. Not as much traffic as Google, but less strict and cheaper prices
AdMarketPlace - adMarketplace | Leading Search Advertising Marketplace - Self Serve Text Ads
EZineArticles - http://www.ezinearticles.com - Publish relavant articles about the topic of your niche and link to your opt-in page domain for List Building. You will generate floods of free traffic.
TrafficVance - http://www.TrafficVance.com - I believe they require a $1000 deposit, but well worth it. They are a PPV/CPV ad network and have a very nice interface.
Lead Impact - Lead Impact, LLC - Another CPV ad network with a good reputation. Lots of international inventory.
Ask - Ask.com - Go here and answer questions related to your niche, while mentioning your opt-in page as a good source of information. Great way to generate free traffic.
Chech also this site, lots of sources of traffic:
The Ultimate List Of Traffic Souces - Media Buyer Association