Library Journal "Digital Libraries" Columns 1997-2007, Roy Tennant
Please note: these columns are an archive of my Library Journal column from 1997-2007. They have not been altered in content, so please keep in mind some of this content will be out of date.
Feed Your Head: Keeping Up by Using RSS
Keeping up has never been easy, although we can probably be forgiven if we think it is harder today. From print magazines to journals, from electronic discussion lists to web logs, there seem to be more sources of information than ever. Wouldn't it be nice if you could filter all this stuff and receive brief notes for what interests you? The idea of a current awareness service is nothing new. What is new is that recent web-based technologies have made it easier to discover and subscribe to these services and to create and manage them. But the potential for these technologies is not limited to individual notification. They are increasingly used for other functions, such as automatically updating web sites. How it works The linchpin technology is RSS, variously described as "RDF Site Summary" (referring to the Resource Description Framework), "Rich Site Summary," and "Really Simple Syndication." But RSS, as used on most sites, has nothing to do with RDF. It is a very simple XML syntax for describing a "channel" or "feed" of information that consists of "items" (e.g., news items) with titles and URLs. In fact, that's just about the whole thing. Each channel is required to have a "title," a "link" (URL), and a "description." Other tags are optional (for the complete spec see RSS 2.0). Each channel has one or more items, of which only a title or description is mandatory, although most items typically have a title, link, and description (often commentary rather than true description). There are optional fields for each item, but simplicity in production and use is one of its strong points. Feeds are typically read through an "aggregator," which allows the informaton to be presented in a variety of ways. Feeds can be either web-based or special client software. Client software is available for all platforms, and Peter Scott's web page "RSS Readers" lists the options. With client software you can subscribe to feeds and have them automatically updated when starting up the client. Steven Cohen's article "RSS for Non-Techie Librarians" is a good introduction to readers and their uses. Web-based aggregators do not require the downloading of special client software, but options for interacting with the feeds are fewer. Finding & searching So how do you find feeds that interest you? One way is by serendipity, which may happen when visiting a web site and seeing an orange "XML" or "RSS" button placed on the page--an indication that an RSS feed is available. But a more systematic way is to visit one or more web-based aggregators--no client software required--that bring together a variety of feeds. A web-based aggregator useful for librarians is LIS Feeds, which offers a simple-to-use web-based interface for reading feeds from library-related sources. General purpose aggregators include sites like Newsisfree.com and syndic8.com. One good way to find feeds is to use feed searching sites to search your favorite topics, then look for sites with information of interest. You can search feeds at Newsisfree.com and Feedster.com, which acts in a similar way to Google. Apparently, Feedster.com also indexes Newsisfree. com, since hits from that site appear as well. The search results include a link to the feed that provides the news item, as well as options to see all items from that feed, just the links and titles, or the raw RSS. Roll your own Where it gets really interesting is using RSS to update web sites automatically. Jonathan Eisenzopf, in "Making Headlines with RSS," offers a Perl module for both maintaining and using (as in a web site) RSS feeds (XML::RSS, dependent upon XML::Parser). Imagine creating an RSS feed of new books arriving at your library. You could allow users to subscribe to this feed and use it to highlight new books on the front page of your web site. Once the basic Perl (or PHP, or other scripting language) is in place, you sit back and do nothing. Now that's my kind of assignment! Of course, creating your own RSS has potential problems. But that is what validators are for. These software programs--often available through web submission--check your syntax for errors. RSS is no different; there is a web site to make sure your RSS is valid according to the specification (see the "RSS Validator"). RSS is a low-overhead way to provide current awareness services within a digital library environment. The XML syntax is brain-dead easy while the software is freely available. We are just beginning to explore how to integrate it into library services. __________________________________________________________________ Link List Introduction to RSS www.webreference.com/authoring/languages/xml/rss/intro LIS Feeds www.librarystuff.net/rssfeeds/lisfeeds Making Headlines with RSS www.newarchitectmag.com/archives/2000/02/eisenzopf RSS 2.0 backend.userland.com/rss RSS for Non-Techie Librarians www.llrx.com/features/rssforlibrarians.htm RSS Readers www.lights.com/weblogs/rss.html RSS Validator aggregator.userland.com/validator