The whole area of tagging and searching is one we are likely to overhaul, if we identify future funding. Bluntly, this is a mess – the original Elgg tagging system broke down when we customised it to create an object called a “resource”.
If you’d like a more extensive answer, read on…
We felt teaching resources were likely to be something that teachers wanted to share heavily, so we wanted users to be able to upload a file and, to avoid this simply being somewhere to share files without any meaning, attach these to a discussion. Within TalkPhysics, technically, a resource is defined as a file attached to either a topic (the start of a discussion) or a comment (the reply to a discussion).
We needed users to categorise their resources, so other users can browse through them, just as users currently browse through the topics and comments after the log-in page. That list of “tags” is the list of possible resource categories. These need to be renamed, to distinguish them from genuine tags, which would be whatever words a user chooses to use, giving the user complete freedom. Particularly, we wanted to tie this in with something like a tagcloud, so it would be easy to see what other users have used.
An analogy would be with iTunes – when posting a resource a user would pick a category set by our administrators, equivalent to song/film/book/etc., but beyond that users could tag by anything they choose, equivalent to jazz/classic rock/psychobilly/etc.
Currently users cannot search using tags – we need to plan quite carefully how users will be able to search for content. Ideally, the main search would return results according to some mix of factors, including the tags, free text and relevance. Ideally, we would even give users a very quick way to rate content (like Digg!), so that is considered in the search as well.