If you haven’t heard of del.icio.us, chances are that you’re not missing much. It’s a bookmark management tool that appeared late last year and that promotes community or collaborative bookmarking, with the bookmarks stored remotely. Further, it’s a big of a shift in the approach to bookmarking: Rather than putting a link in a folder as we’re all used to doing, you apply tags to links, and you can apply as many tags as you want to. This makes for one-to-many categorization without the redundancy of bookmarking something many times, one instance per bookmark category. It also implicitly allows for tiered organization. For example, I’ve spent most of the day googling around for information about two major open source database management systems, postgresql and mysql. I’m trying to collect a whole bunch of data about both servers so that I can make a decision about which to use for a big project I’m working on. Because I got really tired of the bookmark interface and the pain it becomes to categorize things, I started tossing my links into my del.icio.us profile. All results I tagged “database.” Postgresql-specific links I also tagged “postgresql,” and mysql-specific links I additionally tagged “mysql.” Sites relevant to both databases (such as feature-comparison sites) I applied all three tags to.

So far, this probably seems very little different from regular old bookmarking except that the interface has changed. The beauty of it all comes together, though, when you consider the handy fact that you can get at your links via RSS, which can be read in a news reader, displayed as bookmarks in Firefox, parsed in a MediaWiki plugin for display in an article, and so on. By using del.icio.us to store and tag my bookmarks, I’m actually making them very portable. Del.icio.us’s RSS API is very simple and elegant in that it allows you by simply using a correctly-formatted URL to get only the subset of links you want to see. Here are some examples:

• http://del.icio.us/rss/tag/database shows me an RSS feed of all links across the system tagged “database”
• http://del.icio.us/rss/daryl/database shows me an RSS feed of just my links tagged “database”
• http://del.icio.us/rss/daryl shows me an RSS feed of all of my links
• http://del.icio.us/daryl/database shows me an HTML page of all my links tagged “database”
• http://del.icio.us/daryl/postgresql shows me an HTML page of all my links tagged “postgresql”
• http://del.icio.us/daryl shows me an HTML page of all my links

So del.icio.us provides not only an online interface for managing and viewing your bookmarks, but also an alternate format for the links that allows you to plug them into pretty much any RSS-enabled system you want to. This is very cool.

But, as I said at the beginning, if you’re not familiar with del.icio.us, you’re probably not missing much. Chances are that you’re bookmarking things and getting along just fine, and the minor shift in mechanism and presentation seems trivial. Even I felt this way until just today. I thought del.icio.us was sort of a pain to use and didn’t want to have to login to a site to get my bookmarks. But as I started combing through sites about postgresql and mysql and bookmarking them, I found the interface for categorizing the bookmarks to be cumbersome and irritating, and I began to think that I’d probably never even bother to go digging through the bookmarks to find the links. Or I’d have to double-bookmark things to categorize them into multiple applicable folders, and it’d all become very hairy to manage and use. So I tried using del.icio.us, and when you add the popup to your link bar in Firefox, it’s really much simpler to use than the bookmark interface. And when you happen to be a developer who can tweak posts in your MediaWiki extranet to consume RSS feeds and use them to display links, del.icio.us starts to look much more attractive. I’m a convert.

Extisp.icio.us is a nifty visual representation of your del.icio.us tags that changes the font size for tag listings to show which are your most oft-used tags. It has no real practical use, but it can be fun to compare your tags to those of friends and hardcore del.icio.us users (see for example the difference between a couple of my colleagues, one of whom is a reluctant user like me and one of whom is verging on being psychotic about tagging his links). You can see my tags here. Not surpirsingly, postgresql and database are the most prominent tags, with mysql coming in third place.