When I was trying to be a 'pro-blogger', I used to check my logs every day. I've had people respond to my posts within the hour by checking referrals, it just happened they'd check their logs at roughly the same time I was active.

Yes, I was a little obessive at the time, but given some statcounting packages only give detailed logs for the last 24 hours, that's not too bad.

Not discounting that they're obsessive loons, but this in itself isn't proof, just pretty strong evidence.