One recently I've had experience of...the occasional person who will stalk your profile on sales forums. Someone will message me a low-ball offer, and I'll either want to wait a day or two to see if something else comes in, or I'll be at work and not be able to reply that instant. Then I'll get home later and have messages in the vein of 'hey, well it's been three hours since I messaged you, and I've seen you've been online since then! Maybe you didn't get my last message! Where do we stand on that xyz?'.
I've had a couple in the last month or so. It's kind of weird to know someone's frequently checking your profile to see when you were last online, often to put in a offer for something that's far too low anyway. I'll reply when I get time to, or when I've considered the offer. Please stop stalking me in the meantime... :huh: