Here is webmaster world’s info on this. Although others believe social networking has been considered as bad; as searchenginejournal appears to be removing digg links.
I going to speculate here: there is no problem with social networking … what may have changed is that it no longer gives the site as much authority as it had in the past, though networking.
Selling links so others can buy Google authority is something Google has been working to prevent for a long time, hence the term reflux in the title.
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