As we all know paid backlinks is prosecuted by Google, and there is a risk to be penalized. I'd like to share some information how to make paid links look natural. 1) Relevant resources 2) Link in content Don't place links in footer space, widgets. They look suspicious. 3) Anchor Text Be careful with anchor text it should be within the content. 4) No-follow links Use both do-follow and no-follow links since no-follow links are for users not for bot. Google will notice if site contains just do-follow links. 5) Different resources Combine links to target resource with links to other resources. 6) Links in articles for users Avoid optimized press-releases 7) Links from trusted resources Backlinks from spammy directories will lead to penalizing.
No-follow links are not crawled by bot, no-follow links are for getting traffic not for PR. Do-follow links increases PR, that's why Google pay attention for do-follow links as they have gerat influence on SEO.