At the end of the day, webmasters just need to know their sites: chances are your analytics tool is more like a person than a software package, and will classify traffic in irrational ways. I’ve stumbled across website traffic originating from diverse and confusing sources being classed as direct — often requiring a considerable amount of thought and exploration to work out what is happening.
Regarding Link Detox, links it diagnoses as Toxic are generally fine as they're either not indexed by Google or have malware/viruses/etc., but I recommend a manual review of any diagnosed as Suspicious. I used it recently to get started cleaning up our backlinks and some legit sites and blogs were under Suspicious simply because they didn't have many links pointing to them.
Paid search advertising focuses on investing in the right types of ads to achieve prominent positions on search engine results pages and drive traffic to the site. Well optimized search ads can sometimes achieve higher positions than organic search results, while others might be displayed on the right side of the browser page. The success of paid search campaign rests on targeting the right keywords and selecting optimal advertising channels.