The short answer is, you do. What you create and post online - photos, videos, Facebook statuses, tweets, blogs, comments and so on, are your Intellectual property and you own the copyright to them. But when you upload your content online, you grant the site hosting it a licence to use it.
Facebook, Twitter and Flickr’s terms are the same as Instagram’s. Each site can modify, adapt, distribute and use your public posts, comments, photos, videos, tweets and links in promotional material worldwide.
The only way to revoke a site’s licence to your content is to delete it, or close your accounts. Sites may keep back-up copies for a limited time, but can’t use it publicly.
It’s also worth noting that if another user reposts your photos, shares your links on Facebook or retweets you, those posts can still be used by the services in adverts and other places, even if you have deleted your account. You will need to ask that user to remove it if you want to revoke the licence.