Consulting is like waiting for a bus

Every few weeks I am contacted by people wanting help with their development environments. This is a Good Thing for a consultant, but I've started to notice something very odd; the new contacts always come in groups, just like buses. I never get one new contact in a day, it's always either none, two or three.

Now this might be explained if I did more public talks, or groups of colleagues recommended me, but I haven't been able to spot a pattern yet. It's not related to the day of the week either, though I know the budget cycle in companies affects when consultants are hired and fired. Anyone got any ideas? I wondered about synchronization theory but it seems like a stretch.