A new SYO App: Subscriptions Like Mine. It looks for readers whose subscription lists are similar to a particular individual’s. The results are weighted by a “strength” measure that inversely weights the popularity of the feed, so you can find people with similarly obscure tastes, and also tracks the number of overlaps as a fraction of total subscriptions, so that Jay McCarthy isn’t automatically everyone’s friend (though he does show up quite a bit :-).

2 thoughts on “”

  1. Okay, but don’t say you didn’t ask for it!

    The SQL query is below. :n_subscriptions is my total number of subscriptions”, b.n_subscriptions is the like-minded person’s number of subscriptions. There’s lots of room to fool with/debate the strength function. Anyway, here’s the SQL.

    select * from (
    select s2.subscriber_id, count(s2.subscriber_id) as overlap, sum(500*(1/(8+f.n_subscribers))*((1/(5+b.n_subscriptions))+(1/(5+:n_subscriptions)))) as strength, b.text, b.url
    from ff_subscription s1,
    ff_subscription s2,
    ff_feed f,
    ff_subscriber b
    where s1.subscriber_id = :id
    and s2.feed_id = s1.feed_id
    and s2.subscriber_id != s1.subscriber_id
    and f.id = s2.feed_id
    and b.id = s2.subscriber_id
    group by s2.subscriber_id, b.text, b.url
    order by 3 desc
    ) where rownum


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