The data never goes away. As this scholar notes, its more expensive to delete data than allow it to exist in cyberspace.
Certainly there are disadvantages to the long shelf-life of digital info:
- Status posts/tweets sent out of anger/hate/temporary stupidity/etc
- A forever living email from angry student to angry professor, likely destroying professional connections for one/both parties (or maybe not, i don't know)
- Private sexting messages from naive youths circulated everywhere
Other ideas on the advantages of long-term accountability of your digital contributions?