[brey]

Interesting from a machine-learning perspective - but this strikes me as a solution looking for a problem.

If any service needs to know gender (and I'm having a hard time thinking of times you NEED to know gender - dating sites?) - why not just ask? surely in a situation where you're reliant on having accurate gender information, guessing from $firstname and getting it wrong is worse than asking.

[clarkm]

An analogous problem is automatic language and country detection. It's convenient when it works transparently, but can be a huge hassle when it guesses wrong.

[yummyfajitas]

Here is a place where it's helpful and guessing wrong is ok. Consider a movie information site, which for some reason knows your name (but nothing else).

Male homepage: Die Hard, Star Wars, Bridget Jones.

Female homepage: Bridget Jones, Twilight, Star Wars.

Both males and females are shown primarily movies they are more likely to be interested in and your bounce rate goes down.

[vdaniuk]

Why not just ask? More form fields means less conversions. Using the service one can ask for the gender later during the registration process only if confidence in the sex detection is lower then a defined threshold.

[tommorris]

You don't need to know the data for most things. The times you do (dating sites etc.), you need it to be accurate and should ask explicitly.