describes links with the intent to increase PageRank i.e. improve Google Search Rankings.
There are two cases:
Links are created either as
The reason they were created doesn’t (yet) decide if links are dangerous (“toxic”) or not for your rankings.
Only when Google decides that a link is “unnatural”, and Google must be very sure for that, then this manipulative link gets a higher risk for causing a penalty.
The degree to which we think it will cause problems for your rankings is measured in Link Detox Risk® in LRT.
Just because a link is deemed riskier than others, doesn’t mean it’s a toxic link, or even causes a penalty.
TL:DR Manipulative Links are links without NoFollow link tag, created by webmasters or consultants hired by the webmasters. They can be toxic or not.
In a more recent article Mary Haynes came up with a classification of links where Manipulative Links were a separate category to Toxic Links.
This does not make sense, since Manipulative Links only become risky if discovered/detected by Google - and that is not the case for many manipulative links. Why? The industry of link building would cease to exist if Google could spot and penalize every manipulative link.