What do you consider a Spam Site

I have a few sites that registered and are just a subject with links to their sites no real reason for the blog except to link to their Adult Dating site.
Another site is the same and has jumbled words and sentences that doesn't make sense ( I guess this is for SEO reasons to be unique ) with links to their dating site.
I did spam both sites.
How does everyone handle this type of site do you just leave them since they are bringing in traffic and Adsense clicks that make you money or just spam them.

What do you consider to be a spam site

I made a promise to myself that I would not let this multisite setup become a spam farm.
So I'm spamming a blog a day.