What to check before buying an expired domain?

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

• 
  Scott Clark: You`ll want to hit all of the domain classifiers and check the categorization and status of the domains. Here`s a list:
  
  Brightcloud
  Sonicwall
  Forcepoint
  Barracuda
  ReputationAuthority
  Fortiguard
  PaloAlto
  zvelo Live
  Norton/Symantec
  OpenDNS
  Google safesearch
  cisco
  Mcaffee
  
  If you see problems on any, red flag.
  
  Then go back on waybackmachine and sample 5-6 snapshots.
• 
  Stockbridge Truslow: Are they buying the web sites? or the domains? Domains ultimately have little inherent value beyond wanting to have short, memorable brandable names. Even links going to pages on those domains will (eventually) lose most of their value if the links aren`t put back into the same context they were in once created.
  
  On the other hand... good content has value so if you`re getting the sites themselves... that might be worth something.
• 
  Scott Clark: Karina it`s a good point. The content that lead to the link needs to be in-place, or at least something very nearly the same. Wayback machine can help with this too
• 
  Richard Hearne: Don`t forget that domains can generate traffic via those links. If the traffic is well targeted it can be very valuable.
• 
  Karina Kumykova: Stockbridge Truslow and Scott Clark thank you very much for sharing the knowledge, very helpful!
  What the client wants to do is to buy these domains (which are from the same industry) and simply redirect them to the relevant content on their site. That`s all what they want to do, but after they have done it they would obviously expect some results. And the question is either this would be a good investment from SEO point of view or not.
• 
  Stockbridge Truslow: Possibly - if there are good links out there where you have actually VERY SIMILAR pages. Keep in mind that a 301 redirect is for "moving" content. Once the content changes and it`s not simply "moving" - other factors come into play. If the links are still contextually sound - that can help. If they aren`t, it won`t do much.