del.icio.us

Thinking about Semantic Web, crowdsourcing and mostly after reading a recent blog post from Andy I came to believe that we need a 'Tagipedia' (Wikipedia for tags): a place where anybody can tag any uniquely identified web resource (URL) and thus gradually, collaboratively describe the entire Web in more semantically sensible way.

Ironically, large social-bookmarking services (e.g. del.icio.us) have enough data to start something like that, but they have not exposed it in a meaningful way, yet. What we really need is an API call that would return top 10 (or 20) most common tags, across all users for a specific URL. Given that all kinds of widgets can be built, including browser-extensions.

Del.icio.us, where art thou? Can you hear us?

Filtering content through URI tagging was initially popularized by Del.icio.us and is now a common way to quickly navigate content. For instance, in a system that supports this type of navigation, you can constract a URL:

and get a vertical view of the domain data. In this markup, "+" stands for logical AND, whereas "," stands for logical OR.

Following is a PHP code snippet that processes "delicioused" query string into a logical expression (you can modify the code slightly and get an SQL where clause instead). In addition to the original del.icio.us syntax, it allows tags with spaces in them. You just need to enclose those in single or double quotation marks. For instance, the following expression is a valid one: http://example.com/tag/drupal+news,rss,'Steve Jobs'. Note: using quotation marks inside the tag names is still invalid syntax!

And following is the code sample: