ZDNet is reporting that even a year after Cambridge University security researchers reported on how many social networks were not erasing the pictures and videos uploaded by users after the users deleted them, Facebook and a few other social networks and blogging services still have the same problem.

In Facebook does not erase user-deleted content, writer Zack Whittaker describes an experiment he ran showing exactly what happens. Deleted pictures and video files continue to remain available via hyperlinks that pointed to them prior to deletion.

Facebook claims that the files will eventually be overwritten, much like the recycle-bin operation on a PC. However, the Cambridge content deletion experiments show there are reasons to doubt this claim.

Based upon simple experiments conducted by Cambridge, it appears that Bebo, hi5, Facebook, and SkyRock all retain copies of images posted on their servers after deletion even a year later. Services that did remove the content include Friendster, MySpace, Orkut, Tagged, Windows Live Spaces, Blogger, LiveJournal, Xanga, Flickr, Fotki, Photobucket, and Picasa.

There are also concerns about the implicit agreements users are making when they upload content to many of these services. Many of them reserve the right to use uploaded content however they wish, including in advertising, with no reimbursement to users. While this may be great for the services and their users who are hunting for photos and other content to incorporate into their own web sites, it may be a disaster for somebody who inadvertently uploads an embarrassing picture or video and then deletes it only to find that another individual or company liked it so much they are using it widely.

The bottom line is that if you really want to be sure you can limit the spread of content you upload, you probably shouldn’t be putting it on a social network. Instead, consider paying for your own web hosting account at which you have full control over access permissions and the ability to overwrite and delete files. You can link to the files from the social networking sites to retain the advantage of ease-of-use for those you want to be viewing the content.

Further Reading

Senators call for changes to Facebook’s privacy settings

Facebook’s privacy changes: When will it go too far (and will you even notice)?

FBI, Feds collect Facebook, social media data; Why are you surprised?

EFF Posts Documents Detailing Law Enforcement Collection of Data From Social Media Sites

IRS Training Course from 2009 on Using Internet Searches to Find Taxpayers and Income

US DOJ Training Program on Use of Social Networks for Criminal Investigations

Government Use of Social Networks for Investigations