When you don't own your own site or your data, you are dependent on that silo to keep your personal data safe. If you add sensitive data such as credit card numbers, personal details or messages, or log into your account through a password, you must trust that your data is stored securely and will not be compromised. Site Deaths and Site Changes are other reasons why you should own your own identity and content on the web.
This page is a chronology of content hosting sites that have been compromised by a 3rd party.
- 2014-02-15 Kickstarter hacked, user data stolen 
- In a blog post, Kickstarter staff mentioned that "No credit card data of any kind was accessed by hackers. There is no evidence of unauthorized activity of any kind on all but two Kickstarter user accounts" and that "Actual passwords were not revealed, however it is possible for a malicious person with enough computing power to guess and crack an encrypted password, particularly a weak or obvious one." 
- Recommended action: Users urged to create a new password for Kickstarter accounts and other accounts where password was used.
- Why - other problems with using and depending on 3rd party sites
- Google Graveyard (on pinterest.com)