PRISM is a surveillance program operated by the United States National Security Agency (NSA) with direct* access to data stored on Facebook, Google (Picasa) or Yahoo (Flickr). The news about this surveillance program has rapidly spread all around the world. More than 20 days after the revelation by Edward Snowden, a former NSA agent, media are still writing about it.
These intrusions into privacy are now greatly facilitated by the massive concentration of services around some web giants. These giants centralize huge amounts of personal data. Their main business model is to use your personal data to know you as precisely as possible for advertising purposes. It's just a matter of business model. The problem is when your personal data are used "another way", and PRISM shows that it's possible.
Ensuring privacy is still possible. Website prism-break.org lists alternatives for these services, such as messaging, search engines or... photo sharing! Piwigo is listed against Yahoo Flickr and Google Picasa Web Albums. Use free softwares, which can be reviewed for privacy respect. Decentralize, by hosting you in a country that respects privacy or even better self-host your Piwigo.
By using Piwigo you contribute to freedom on the internet.
* the degree of "direct" access is at the heart of the controversy, and we will probably never know what degree of "direct" access the NSA has