SemanticMetadata.net

Less than 20% of Flickr images tagged …

While writing a scientific paper on tag recommendation I checked - just out of curiosity - the share of images tagged by their uploaders on Flickr. I found out that 4 out of five images are untagged and that less than 15% of images have 2 or more tags.

My method and detailed results: In general one would need a random sample for such an investigation, but a truly random sample is hard to obtain without access to the data base. Therefore I just grabbed 20,004 images from the RSS feed for recent uploads and counted the number of tagged images. Easy enough I also computed the confidence interval:

• In my sample 3,650 images were tagged with at least one tag, that makes p1=18.25%
• With alpha=0.99 p1 is in [16.84, 19.66].
• That leaves more than 4 out of 5 images untagged.
• Also in my sample 2,628 images were tagged with at least two tags, that makes p2=13,14%
• With alpha=0.99 p2 is in [11.9, 14.37].
• That means that less than 15% of the images images have more than one tag.

Del.icio.us Tag Co-Occurrence Demo App

You might all know del.icio.us, the social bookmarking service. As I use this a lot and also did some research in this direction recently (see e.g. here) I wanted to try out more Within my preparations for the Multimedia Information Systems course this semester I checked in how far LSA (latent semantic analysis) can be applied to tags and made also a small demo application. The demo fetches the RSS feed from a given user name (leave the name field blank for random names, separate multiple names by commas) and computes a co-occurrence matrix after a latent semantic analysis. Note that only the last ~30 entries are in the feed. You might then select a tag from the combo box and find the related ones.

The tool can be accessed via Java Web Start here. Drop me a line whether you like it or not.

Related links:

• Start the demo application (Java Web Start)
• Jama Matrix Library
• LSA on Wikipedia
• JGoodies Looks - used to male it looking good