As you know, PR firms and other nefarious enterprises often purchase accounts for the purpose of astroturfing. There are various outfits which cater to this demand by creating and aging accounts on various social networks. Most reposters are simply accounts being aged. These accounts are then used in various PR campaigns.
One of the biggest PR firms in the world HP Gary (mostly works for the US government and Fortune500 companies) is known to have a specific software for creating aging and managing accounts.
How do we prevent this practice?
A few ideas that come to mind:
- Prevent creation of multiple accounts from the same IP range.
- Strongly discourage reposts. Demand OC.
- Delete inactive accounts after reasonable amount of time.
- Make downvotes cost karma.