I may be a little slow on this, but this blew my mind beyond repair

I thought threads are called threads because of the way discussions were first visually arranged on message boards (and still are mostly). Grouped in a hierarchy by topic, with any replies to a message arranged visually near to the original message and linked by a line (the "thread"). But I could be wrong, I am quite a lot of the time.

So, if we're all on the web, and we make threads, are we spiders?