If so, how do you announce it in a newsletter without it looking like spam to them?
Some great tips above. Those who have followed me for a while online have witnessed many ideas I have began to develop and then tossed by the wayside. Many domain names and Twitter accounts archived or deleted. There is no problem with transitioning your previous customers to your new venture. You just want to be careful that you do nothing that asks to much of them or creates any confusion. If your previous subscribers were paid, I would suggest offering them some sort of a discount. If there is anything overlapping, don't ask them to pay again. Give them 2.0 for free.