Chapter 7: Application Outlook 301 Figure 7-4. Posting an image from a mobile phone to Flickr with LifeBlog (reproduced by permission of © Nokia). tasks. Content can be conveniently uploaded to the site from mobile devices. Figure 7-4 shows how an image is posted to Flickr, with an added title. Tags are simple text strings associated with the images, which creates a form of metadata. People can add arbitrary tags freely. Millions of 15 tags have been defi ned so far, with the most popular tags involving tourism, scenery, pets, families, parties, weddings, holidays, and so forth. Tags create free-form collections of metadata, known as folkson- omies, as opposed to taxonomies in the knowledge representation community (section 4.3). This grass-roots approach to metadata appears attractive, as tags are simple to contribute, simple to understand (for humans), easy to index and search, and readily embedded among HTML. However, since the metadata symbols are solely text, their semantic meaning is only clear to humans. For instance, a city might be tagged with “New York”, “New”, “York”, “NY”, “New York (NY)”, or combinations thereof. These equivalent tags appear as separate ones to Flickr. This is a problem for automated analysis, but many of the users of the site will not care, happy to fi nd their images with a process they are used to – keyword search. 7.3.2 Content Rating An interesting loose community has developed around the Hot or Not! 16 Phenomenon. The idea is very simple: you submit your photo (your portrait, to be exact) for other web site visitors to rate, or you rate 15 The most popular tags are listed in: http://www.fl ickr.com/photos/tags/ 16 http://www.hotornot.com/