In TCP (Transmission Control Protocol, which controls about 50% of all Internet traffic) has an interesting mechanism embedded within it.

The protocol itself is designed to guarantee intact delivery of data over unreliable mediums (bad devices, bad wiring, etc.). It can detect dropped packets and malformed packets, and takes it upon itself to retransmit in the case that these are detected. It is also designed to automatically deal with network congestion, should the situation arise, but it does so without talking to any of the devices in between.

It does this by slowly increasing the "window" of packets it has that are en route. This means that, at the beginning, it will transmit 10 packets, and then wait for acknowledgement from the other end before sending anything further. As that window size increases, the amount of packets en route increases, and the overall throughput of the connection increases because the sending host is no longer waiting in between transmissions.

However, at some point, the connection runs out: either you exceed the capacity of your wire, or a device in between you and your destination decides to limit you (this is how your Internet connection is limited to a certain speed, your modem will start dropping packets if you exceed a certain rate). TCP assumes that this is caused by "congestion," and shrinks the transmit window to contain less packets (and also slowing down your bandwidth). It then starts to slowly increase the number of packets back up again, until it is inevitably rate-limited and it drops back down.

It looks a little like this:

The reason I bring this up is that today was the first day of work at my new job. And TCP congestion control was what I was thinking about because that would be exactly how I hold conversations with other geeks: talk about increasingly geeky shit until somebody's eyes gloss over. Then back off a bit, and then slowly ramp back up.

Sort of a nerd handshake. Or nerd chicken. But in the end, information is communicated, and you establish a clear level on which to communicate with people.