What does that term mean?

Of every person told this quote, they tell it to > 1 other new person on average.

So the "r" stands for what, repeatability? Where did this jargon originate (and more importantly, why do web searches only turn up insulation values)?

reproduction:

It is a math model for infectious disease http://en.wikipedia.org/wiki/Mathematical_modelling_of_infec...

For a virus, the average number of people a sick person infects. If r < 1, the spread is self-limiting. If r > 1, it spreads exponentially until r drops (because, say, enough people develop immunity).

So the r-factor more or less measures the capacity of a word/phrase/blurb to propagate itself as a meme?