I'm not sure what worries me more in Charlene Li's post about Facebook's new Beacon advertising system - the problems with Facebook Beacon or the fact that Charlene has two Facebook accounts, one for her analyst persona and the other for her (apparently) real persona:
"I'm not sure of all of the details, but I suspect that if I had logged into my "personal" Facebook account first (yes, I have two Facebook accounts and unless you know my personal email, you won't find my truly personal Facebook profile), that Overstock activity would have been logged to that Facebook profile."
On the Facebook issue, I can see some value in Beacon if the user has the right level of control over privacy. On the other hand, the cookie-based approach sounds a little clunky. But the persona issue I find more interesting. Now, I know you shouldn't throw stones in glasshouses because like Charlene I limit the personal information I publish on the Web but in terms of my online identity there is only one. Maybe I'm being a little naive but I'm a little more disturbed about the impact of people developing fake relationships with fake people in Facebook than I am by a clunky marketing system that needs some fine tuning. In that respect, that's the really compelling reason for Facebook to get its marketing systems and privacy control working right and working together just so we can keep our online relationships - professional and personal - real.
BTW Some of the comments in a reply to Charlene's post are worth reading - you have to feel sorry for the guy who bought an engagement ring and Facebook then announced it to his friends (ruining the surprise).