Ask HN: How can a community website make money to sustain itself?

I am thinking of creating a community website to undertake community improvement intiatives. I am curious to find out what options are available in order to make sure that the site is able to sustain itself. The possible options I am thinking of are -

    Asking for donation
    Google Ads
    Referral links to Amazon etc.

Are there any other means of making some small revenues for these types of websites.