A person who shares or likes or retweets everything they come across?
From Urban Dictionary:
Tweet monkey
He would have Tweet Diarrhea - Tweetspew has also been coined although there is an account featuring people spewing with that name too
For someone who's twitter account is largely unoriginal content I'd describe them as a Retwit.
My suggestions would be:
serial retweeter/resharer
as someone who retweets or reshares repeatedly, or
social media butterfly
a play on "social butterfly" which is sometimes used to describe someone who flits from table to table at parties socialising with different groups
If they are chiefly doing this on Twitter you could call them chirpy:-
- Characterized by chirping tones: a bird with a chirpy song.
- Tending to chirp: a chirpy parakeet.
- Cheerful and good-humored: a chirpy radio announcer.