Don’t spam people, it is not cost effective. You are much better off trying to build genuine relationships, even if just token ones, rather than building giants lists of people to things and bothering everyone.
For example, instead of going to 10 forums, and leaving 10 spam messages, that generate you 1 click and 10 deletions mere moments after, spend that time going to 5 forums, asking a genuine question, and then go back a few times to do the same, before dropping your spam in the middle of it.
For example, if a new person comes to Fluther, and asks a question with a link in it, and it is obviously spam, then it will get deleted. However, if you spend a couple of weeks dropping in from time to time, and building up a reputation, you can eventually work in a link discretely one day, and get yourself 50 hits or so.
You will want to start building accounts, on all major sites. Use the Alexa rank and sign up to the top 500 social sites, and start participating.