Google Adsense and Viglink/Skimlinks are completely different programs. Adsense is an ad network which pays you on pay per click basis whereas Viglink and Skimlinks, both are affiliate networks that pay you for every sale driven from your blog.
Advantages of Viglinks and Skinlinks are:
1. You do not need to create an account with every affiliate network.
2. Just add Viglink/Skimlinks code to your blog and whenever you add any normal link to Amazon, eBay etc. it will automatically become an affiliate link.
3. With only one account you will get access to over 12,500 merchants of Viglink or 17,000 of Skimlinks.
4. You will get the highest possible commission e.g., with Amazon affliate your commission increases with every sale upto 8% on a per month basis. But with Viglink or Skimlinks you will get 8% on every sale you make.
5. Minimum payout is very less, $10 for Skimlinks and $25 for Viglink.
6. You save a lot of time.
I recommend you to try both programs, so that you do not miss any merchant in their circle.