1. Many male developers assume that they are in an all-male environment and behave as if they are. Sniggering schoolboy humour, edgy jokes, sexual jokes are a part of young male pack behaviour that is relatively harmless in all-male environments. In mixed environments they are not only inappropriate but they send the signal to other people that this is a young, male environment. Only.
To be inclusive we need to drop the male pack mentality. It is right to call out this behaviour, especially in public environments: conferences, keynotes, hacker sessions. It is also right to call-out all-male speaker-panels for the same reason.
2. Something 'sexy' is not automatically 'sexist' — it all depends where the power is. A tits-tracking app is (apart from being male-pack humour) an example of those with the power in the room making fun at the expense of those less powerful in the room. It is also 'objectification' — the reinforcement of a women's place as being an object to look at or to have sex with, rather than being an intellectual equal. The women in the room are expected to laugh it off or be subject to more ridicule: "it's just a bit of fun" — This is classic bullying behaviour. As long as these rooms are mostly full of men, women will be powerless to do anything about it. It's no surprise that the fight-back starts only once these incidents hit the internet: our community is bullying women.
3. A group of women ironically creating a pack-track app that tracks penises wouldn't automatically be sexist. It would almost certainly be funny and ironic for two reasons: 1) the balance of power is against the women 2) they would be shining a light onto male-pack behaviour. Men, still holding the balance of power here, should be able to laugh such a thing off. Sadly many of you here wouldn't.
4. Commentators here have a fundamental misunderstanding of what Feminism and Sexism is. They are confusing equality with uniformity.
Feminism is a civil rights movement. It is about equality of power and opportunity for women. Much like anti-racism it isn't about people making jokes about each other: it is about segregated jobs, inequality of opportunity, economic discrimination.
Seeking equality is not the same as seeking uniformity. Just because you can find an example where women have more jobs in a sector doesn't mean that it is sexism against men. It is often the opposite: low-paid caring jobs around cleaning and child-rearing. The low-pay & low-power is the result of years of sexism, as is the usual case where men who get into these roles quickly rise through the ranks and far more likely to become bosses (despite their under-representation). Some women protect these environments as all-women precisely to give them a chance at promotion. While I don't condone this behaviour I can at least understand it.
Equality is the big picture; the balance of the scales. Men still hold the top jobs, the powerful jobs: Judges, Police Chiefs, Prime Ministers, Presidents, Board Members. Equality of opportunity is the ability to rise through the ranks based on ability not sex.
5. Most sexism is silent. We do it without knowing we are doing it. Men appoint men because the other men are men like themselves. Men know how to talk to men; Geeky men more-so. We fill our conferences with men, our panels with men, our keynotes with men because it is an easy thing to do. We promote bright young men because they remind us of ourselves. We tell ourselves that we are simply picking the best.
Combating this silent sexism is hard. As long as all we see is men everywhere then we will continue to be silently sexist and women will continue to silently vote with their feet.
6. It is sexist to say that men are better at programming than women. Unless you have scientific proof that I haven't seen: women are perfectly good at hacking. Any woman who has chosen a career in IT despite the discrimination stacked against her (see above) is already extraordinary yet we will generally treat her less than an ordinary hacker.
Women make up 51% of the population, they are out-performing men in school & university here in the UK and they should therefore be over 50% of our community. But they are not. This is somebody's fault and it is most probably ours. We have created an environment that is hostile to these bright young women and it is lunacy: we are throwing away half of the talent.
If we are throwing away half the talent how can we possibly be hiring the best? Half of whom we hire must be sub-standard!
Which brings me to:
7. Positive discrimination is the only way to go for our industry. We need to adjust our gender-balance by removing our obvious gender-bias. We are currently clearly discriminating against women so we should address this positively.