Common Questions on SEO on and off page

Table of Contents

OFF PAGE SEO

Great sources if you want to build up your backlinks and website traffic

9,200,000+ Traffic Sources for Your Blog or Website

When I find a social book marking site. Should I bookmark everything or just one main link to the home page of my domain?

I know I need to disavow bad backlinks. How do I tell what is a bad link. Some links show up in back link reports as really strong influences. But I click through to see my backlink and everything I click on the page leads to some porn. Is this a bad link then?
Is buying a bunch of cheap backlinks bad? How about testing it by having them backlink a specific article. If it is bad can it damage the reputation of my whole multi niche website?
How do I Disavow bad links? –> https://support.google.com/webmasters/answer/2648487?hl=en