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[The researchers] identified several NetFlix users by comparing their “anonymous” reviews in the Netflix data to ones posted on the Internet Movie Database webs

[The researchers] identified several NetFlix users by comparing their “anonymous” reviews in the Netflix data to ones posted on the Internet Movie Database website So why sue netflix instead of IMDB? Additionally, is there an expectation of privacy when posting movie reviews to public websites?

electromagnetic 17y ago
I believe the suit is targeted directly at Netflix because it allegedly violated stringent privacy laws related to video rental data. Whether Netflix violated the persons privacy or not is debatable (hence it hasn't been settled yet), however they certainly don't appear to have the intent to keep peoples privacy: > The suit is also asking the court to stop Netflix from launching its promised second contest to improve the recommendations — this time giving out user data that includes ZIP codes, ages and gender, along with movie ratings and ID numbers substituted for user names. I'm not certain how ZIP codes work in the US, I know however that my postal code for my childhood home in the UK could place me within a 30 house range on my street. Given age you could extract this down to ~7 people, given sex it was down to 3. Being 1 of these 3 people means I have a 50/50 chance of identifying two 'anonymous' people based solely on postal code, age and gender. Lawsuits usually come down to intent, and Neflix arguably doesn't have the intent to keep its users privacy if it's intending on releasing ZIP, Age and Gender information.
- Retric 17y ago
  It depends on the type of Zip codes. Basic Zip codes are only 5 digits so ~30,000+ people per Zip code. However, Zip + 4 codes dramatically reduce that.
  - electromagnetic 17y ago
    Considering ~3% of Americans are NetFlix subscribers that means only ~900 people per Basic Zip might be subscribers. Gender will half this to ~450 people, and considering that (IIRC) each 5-year population group has on average ~5.8% of the population in it with a median age of ~38 (where the percentages are hitting 7.8%), but let's say an average 1.2% of the population is of any individual year of age. This means, on average, you should still be able to place someone down to ~5 people. God forbid you're a 110 year old using netflix. If netflix is releasing it in 5-year groupings that still puts you in a group of ~30 people for grouping of ~30,000. I'm unsure if any data release like this counts as anonymous.
    - Retric 17y ago
      I don't think Netflix is going to release their customer list the first reduction is not directly possible. Also splitting the population into equivalent size groupings is a normal approach, so you might start with 18-21,21-26... and end with 85+. Also, it's normal to add / remove ~1% of your sample to remove some edge cases and muddle the waters.

electromagnetic 17y ago

I believe the suit is targeted directly at Netflix because it allegedly violated stringent privacy laws related to video rental data. Whether Netflix violated the persons privacy or not is debatable (hence it hasn't been settled yet), however they certainly don't appear to have the intent to keep peoples privacy: > The suit is also asking the court to stop Netflix from launching its promised second contest to improve the recommendations — this time giving out user data that includes ZIP codes, ages and gender, along with movie ratings and ID numbers substituted for user names. I'm not certain how ZIP codes work in the US, I know however that my postal code for my childhood home in the UK could place me within a 30 house range on my street. Given age you could extract this down to ~7 people, given sex it was down to 3. Being 1 of these 3 people means I have a 50/50 chance of identifying two 'anonymous' people based solely on postal code, age and gender. Lawsuits usually come down to intent, and Neflix arguably doesn't have the intent to keep its users privacy if it's intending on releasing ZIP, Age and Gender information.

Retric 17y ago
It depends on the type of Zip codes. Basic Zip codes are only 5 digits so ~30,000+ people per Zip code. However, Zip + 4 codes dramatically reduce that.
- electromagnetic 17y ago
  Considering ~3% of Americans are NetFlix subscribers that means only ~900 people per Basic Zip might be subscribers. Gender will half this to ~450 people, and considering that (IIRC) each 5-year population group has on average ~5.8% of the population in it with a median age of ~38 (where the percentages are hitting 7.8%), but let's say an average 1.2% of the population is of any individual year of age. This means, on average, you should still be able to place someone down to ~5 people. God forbid you're a 110 year old using netflix. If netflix is releasing it in 5-year groupings that still puts you in a group of ~30 people for grouping of ~30,000. I'm unsure if any data release like this counts as anonymous.
  - Retric 17y ago
    I don't think Netflix is going to release their customer list the first reduction is not directly possible. Also splitting the population into equivalent size groupings is a normal approach, so you might start with 18-21,21-26... and end with 85+. Also, it's normal to add / remove ~1% of your sample to remove some edge cases and muddle the waters.