I just returned from the ECML Data Mining Workshop and one talk I found particularly interesting. In the talk Network-based marketing: Identifying likely adopters via consumer networks (S. Hill, F. Provost and C. Volinsky) presenter reported on a successfull marketing campaign. Rough summary from the talk: A phone company was introducing a new service and from past experience they had twenty-something marketing segments for people that were likely to buy that they would write to, call or otherwise inform of the new service. Since the phone company has access to the call records they extracted a list of friends these likely buyers frequently call and started marketing to these people as well. The cool part is that the response rate from the friends was about 3 times higher than the likely-buyers response rate (or was it even the buy-rate). That said, so many companies now started to collect (or have available to them) social networks data, e.g. Skype (now EBay), Google (GMail invites), MySpace, Facebook etc. Most likely this will change the ways of advertising quite a bit. Sidenote: the companys lawyers felt this is legal, because the company owns that call data. Interesting how this is legaly different from the NSA-survailance-program the US government has been doing.