SkimLinks works very similarly to VigLinks in that it is designed for bloggers who don’t want to do a lot of hands-on work to participate in an affiliate program. SkimLinks also works much like VigLinks in that it uses a plugin or script to create dynamic links in your content to send visitors to higher paying offers from merchants. SkimLinks claims to work with over 24,000 merchants/advertisers.
Affiliate networks offer you access to multiple (and by multiple, we mean hundreds if not thousands) of individual affiliate programs. They basically work by simplifying the signup process - instead of applying to become an affiliate for a each product you want to promote, you simply apply to join the network and instantly have access to hundreds of different affiliate offers.