Data milestones can get a little, well, boring. While it is amazing that there have been billions of downloaded songs, and millions of Facebook accounts, and kajillions of whatever else is out there, the zeroes are getting a little overwhelming.

That said, services like Flickr, which are free and provide some very cool features to their users, deserve a bit of celebration. I could never have so clearly imagined the lives of close family members as I can because I can see pictures of where they live, work, and play. That’s why I’m willing to celebrate Flickr’s five billionth photo.

According to the Flickr blog, user “yeoaaron” uploaded image number 5,000,000,000 yesterday. Here’s to 5,000,000,000 more!

Most everyone has seen or heard of social networking sites affecting privacy in crazy ways. They’ve cost people jobs, ended countless relationships, and in the best cases, resulted in some bruised pride. As more people get hit, more users are choosing to remove questionable content from their pages, but the content’s not necessarily gone.

Ars Technica’s Jacqui Cheng put recent findings from Cambridge University researchers to the test with some unsavory results. Turns out your deleted pictures may not be as far gone as you’d like.

Jacqui tested Facebook, MySpace, Twitter, and Flickr with the same method. She deleted pictures from each site on May 21st and then watched the direct links for six weeks. Twitter and Flickr were both good, truly deleting the pictures after a hard refresh. MySpace and Facebook didn’t fare so well. Direct links from both sites still produce the “deleted” images, some six weeks after they were pulled.

Moral of the story? Continue to censor your drunken impulses, particularly with regard to the pictures you upload.