I imagine they would leave it alone as much as possible, because they aren't sure what's bringing in all the traffic. Wouldn't want to be another Digg.
50M sounds like a vanity number of unique visitors.
Still a lot but not comparable (thus actionable or risky-to-destroy) to eg "50M active users"
(to be fair twitter/fb and co usually also communicate the unique visitors afair)
Digg did a redesign that was absolutely horrible and created a huge backlash. Because Digg did not create a backup/proper versioning, they couldn't go back to the old design, and people migrated to reddit. The rest, as they say, is history.