Bottom Feeder Categories Proposal
05/17/03 Send comments to Rich Demers.
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RSS allows the specification of category metadata for each item of a feed. What should aggregators such as BottomFeeder do with this metadata?
From the Dublin Core Metadata Initiative: a subject (or category) is the topic of the content of the resource. Typically, a subject will be expressed as keywords, key phrases or classification codes that describe a topic of the resource. Recommended best practice is to select a value from a controlled vocabulary or formal classification scheme.
- Display the category specified as a string for each item in a feed.
DONE!
- Display cross-feed items in a category.
- Treat categories as a way to select the items to display in a transient table.
- How should the user select categories to display?
- An input area to specify a category to see?
- Search by category in the Search Tool?
- A drop-down of available categories to select?
- Is each display of a category a separate event? With no history (old / new) of items in a category seen -- as other searches are in BF 2.9. Or do we want the resulting category to be a system object with additional behaviors?
- The category space is sparse and the user should not have to guess what categories can be selected or specified.
- Presuming that BF will eventually support an enhanced search tool that supports complex queries based on item metadata (the DC metadata elements), the user should be able to include categories in such a search.
- Allow the user to define pseudo-feeds consisting of items of real feeds in a specified category. The user could then put a notifier on a specific category pseudo-feed, make all of its items old or new, query its items, etc.
- Real feeds have a URL as a property, but pseudo-feeds would have a category specification.
- Display the items in a pseudo-feed as new or old (as in real feeds).
- All items in a pseudo-feed can be made old or new (as in real feeds).
- It is the item that is old or new, regardless of which feed or pseudo-feed it is displayed in.
- A "subscribed pseudo-feed" is one that is automatically updated whenever real feeds are updated; otherwise, they are updated on demand. The arrrival of a new item in the pseudo-feed triggers the availability of the New Items view, whether or not the real feed that contained the item is subscribed. If the real feed and the pseudo-feed are both subscribed, only one copy of the item is in the New Items view.
- If a pseudo-feed has a notifier, the arrival of a new item in the pseudo-feed triggers an Alert, whether or not the real feed that contained the item has a notifier. If the real feed and the pseudo-feed both have notifiers, there is only one copy of the item in the Alerts view.
- The concept of pseudo-feeds is not limited to items in the same category; it could be extended to include items derived from real reeds through any selection process based on metadata or text queries.
The next simplest thing that could be done is to display the cross-feed items of a category in a transient table as the results of a Search Tool enhanced to search for items by category. A follow-on is to support the creation of pseudo-feeds based on category.
How to handle categories from different feeds? The simplest thing is to display category string values -- which is DONE! However, to identify and display cross-feed categories, BF needs to correlate the string values of different feeds under a user specified or selected category name. One possibility is to define class Category and create an instance for each category the user identifies. Pseudo-feeds could then be created for user selected Categories.
How to equate categories from different feeds? - By equivalent elements in different modules (eg, category and dc:subject).
- By matching tag content strings -- with user help to equate strings with the same meaning.
- By matching with known encoding schemes (Library of Congress Subject Headings). This should be postponed until better defined.