How would you assess the value of a backlink?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Neil Cheesman: Firstly, doesn`t it depend on what `value` the Dun & Bradstreet directory has? I would perceive the directory+buying service part of their marketing...
• 
  Jenny Halasz: no. don`t do it. They will never leave you alone again. If they`re claiming it has SEO benefits, it will only be a matter of time before they get hit and have to make them all nofollow the way that BBB did.
• 
  Neil Cheesman: Surely you should only `buy into it` IF you are going to use their services...
• 
  Jenny Halasz: They don`t care about valid data anymore. They only care about getting paid. I wouldn`t trust their info at all... their listing for my business shows I have 3 employees (I have never had even one), that I do 150K per year (waaaayyy off), and that my phone number (which I had a long time ago, but never associated with the business) is wrong. If you call it, a woman named Sharonda (sp?) answers. I`ve tried multiple times to update this obviously wrong data and all I get every time is a sales pitch and they never do update it.
• 
  Neil Cheesman: as above.. would only register with them if using their service... (and I think they are quite expensive... an expensive link that`s for sure...)
• 
  Neil Cheesman: ps.. I have never had anything to do with them.. :)
• 
  Jenny Halasz: Also - I`ve never heard a local search expert advocate for getting a link from the D&B for citation value - not like the BBB or yellow pages.
• 
  Dan Thies: If they are using SEO value as a primary selling point, it`s likely that there is very little value period.
• 
  Neil Cheesman: They would probably charge more to have the link removed... #lucrativebusiness