I've been chasing the 7 ghosts since mid-November. I found 4 of them within a couple of days of getting the quest, but since then... I'm feeling totally unhaunted. They haven't said "boo"!
I've achieved all the completist badges, taking care to explore the likely dark spots.
I've checked out all the places that glitch-strategy.com suggests.
I've ranged all over, time after time.
Are the ghosts still out there? Any advice for finding them?