Ticketmaster hates deep linking because it wants to be sure its visitors go through several pages of ads before they get to the information they want. (I first published this page back in August 2002.). It doesn’t take that much friction to cause a problem. Even one extra step can have as significant an effect as twenty.
For people with open, descriptive profiles on Facebook and LinkedIn, public Twitter feeds and other kinds of information visible in the world, their door is pretty much open. This is the era of “friending through online social networks. Some people have already done so much friending that they’re fed up. This is a social medium.