Posting to Hacker News does do something though. Not in isolation.
https://en.wikipedia.org/wiki/Common_knowledge_(logic)
There's something very powerful when I know what you think, and then you know that I know what you think. When mass understanding foments, common knowledge kicks in and there will be (it's already in the works) a sort of large scale adknowledgement that this is the will of not only us as individuals, but also us as masses.
[I will leave my usually blurb about documented programs in the US and elsewhere that specifically target and derail the forming of such community consensus and on the flip side manipulate media to create desirable consensus.]
Posts on Hacker News will only go so far, but as a community that makes recommendations and gives technical advice and knowledge to the broader community - and as patriots and democratic citizens - we can (and I do) discuss these issues without bashfulness to everyone we are close with.
People care. Old people care and young people care. Democrats, Republicans, Centrists, and Populists care. Religious people care. So do atheists.
Information is key and the media has a really poor record - even (especially) with the handling of the Snowden disclosures. The EFF and ACLU can only bring so many cases to court. _We_ need to be the reliable source of information - for those who look to us for technical advice and information.
And we need to demand an option during elections. This next (national) election is going to be another 'security year'. Screw that. Neither Ebola nor ISIS pose a credible threat to the United States. The real issues are class issues, democratic issues, police state issues, social issues, etc.
Your vote doesn't count for a whole lot. But all of our voices (for the most part) do. Man, it's depressing I had to qualify that... Anyway - posting to HN absolutely contributes. It just isn't the only place you should have your voice heard.