Word of Mouth means more these days...
Gordon Weakliem had an interesting comment on Malcolm Gladwell's book on Sam Ruby's blog:
...the phrase "[The Internet] dramatically speeds up the rate at which reputation spreads by word of mouth" seems to be a key.
I find this to be particularly true with the advent of blogging. I was speaking to a users group recently and Chris Sell's name came up, and the question was posed "how did he become so famous?" Some people had read his book, some had read his blog, and others had seen him speak. But the general consensus was, via word-of-mouth, that Chris was a good enough fellow. No doubt he has been mentioned in e-mails, quoted in USENET posts, and held up as an example of a highly competent developer and clever architect.
This begs the obvious question, if there was no Internet, how long would it have taken for a Chris Sells (or Don Box, or Clemens, or Sam Ruby, or Dare Obasanjo, or anyone in an obscure technical vertical as ours) to become "well known and thought of."
I don't think it can be underestimated how quickly word-of-mouth spreads on the Internet. It would be interesting to have a race between a rumor and a virus. The rumor would be propagated only by humans, and the virus competes programmatically. I suspect it would be pretty close.