We were seeing a significant drop in Google (organic) traffic for Server Fault after instituting this "follow links if enough upvotes post-edit or post-create" policy.
We traced it back to what we currently think are a string of posts on Server Fault that got nofollow removed through "trust", but were being interpreted by Google as link farms or spammy pages. Examples:
- How to remove IIS/ASP.NET Response Headers
- hardware recommendations for a DIY storage system based on ZFS
- How do you secure your mobile computers?
- HP Proliant DL380 G4 - Can this server still perform in 2011?
- How to troubleshoot Windows? Post your checklist
So, for the record, we're not 100% sure, but this is the only thing we've changed -- and the evidence is fairly damning so far, though not quite conclusive. I had many reservations about risk in doing this at all, so the idea of following any links is going away for the forseeable future until we rule out other possibilities.
Back to the old safe, sane, policy that I advocated from the first day this came up: no external links are followed.
-- Jeff Atwood
Stack Overflow is driven by incoming links—ranking SO results high in Google is crucial—and it is those incoming links that bring people to the site.
We really should take your comment about "not getting the Google juice they deserve" to heart. Stack Overflow is about making the Internet a better place and giving back.
rel="nofollow" serves a purpose but, perhaps, there is some criteria that can determine when a post surpasses the potential for wide-spread abuse and can be placed in the "giving back" column. Some combination of:
- Reputation (i.e. trust)
- User History (i.e. tracking tendency for a user to link to the same domain)
I'm not pretending to know the criteria, or even if there is a criteria. But agree with the principle of your request, though.