In a recent post I said that OPML would be a great format for sharing attention data, but I wasn't sure whether this would be possible due to uncertainty over OPML's support for namespaces. This afternoon I talked with Dave Winer and Steve Gillmor, and to make a long story short, I'm happy to report that namespaces will be supported by OPML. So an attention namespace for OPML seems like a fine idea at this stage.
As I mentioned previously, FeedDemon already stores attention data in OPML, but it uses a proprietary
fd: namespace which relies on attributes that make little sense outside of FeedDemon. What I propose is that aggregator users and developers have an open discussion about what specific attention data could (and should) be collected by aggregators.
Although there's a lot of attention data that could be stored in OPML, my recommendation is that we keep it simple - otherwise, we risk seeing each aggregator support a different subset of attention data. So rather than come up with a huge list of attributes, I'll start by recommending a single piece of attention data: rank.
We need a way to rank feeds that makes sense across aggregators, so that when you export OPML from one aggregator, the aggregator you import into would know which feeds you're paying the most attention to. This could be used for any number of things - recommending related feeds, giving higher ranked feeds higher priority in feed listings, etc.
Although user interface and workflow differences require each aggregator to have its own algorithm for ranking feeds, we should be able to define a ranking attribute that makes sense to every aggregator. In FeedDemon's case, a simple scale (say, 0-100) would work: feeds you rarely read would get be ranked closer to zero, while feeds you read all the time would be ranked closer to 100. Whether this makes sense outside of FeedDemon remains to be seen, so I'd love to hear from developers of other aggregators about this.
Beyond rank, what other attention data do you think aggregators should collect? And how should they use that data to serve you better?