Yes I agree with Rob. If you have multiple niche lists stay specific to that niche. you'll always be able to market to demographics of that list as well. Say for instance your marketing to the baby niche and your marketing baby toys, and baby clothes or something like that. A question may be, "What other products might people that have baby's be interested in?" they may be interested in baby food coupons, saving on diapers or baby health information product or services as well. The important thing I think is to stay in the niche and market to demographics and that opens up many more products/services within that niche

Having the statistics for your campaigns is very important. Aweber or Get Response are good. Having a complete suite of services is better if you can find it.

One last thing, I believe that it is a great thing to give helpful information like articles that you set up on Google so that you're giving useful information to your list members. They will appreciate the help--I know that I would