If you intend to do any research online, you must utilize a Panel. You can't just send email to people who have not previously agreed to participate. That is spam, and it will get a very negative reaction and potentially damage your company's reputation. So you have to find people who have already said they'll take surveys when you want to conduct an online research project.
Managing a Panel requires three things: tools, time and expertise. You'll need tools to be able to create and maintain the online community environment for your panelist (website, interactive login area, prize catalog, etc.) and you need a response center to respond to and track communications with panelists.
You'll need time to interact with your panelists, especially if they are your existing customers, so they feel appreciated and get responses quickly. And you'll need expertise on the nuances of survey programming, lottery and sweepstakes rules, referral network strategies, privacy policies and similar issues in order to answer questions from your Panelists.