As I noted in December, I've been keeping track of the feed items that I find interesting in Google Reader. My method has been to "star" the items, which is a statistic that Google Reader keeps track of. Here is the summary in the Trends view: "From your 128 subscriptions, over the last 30 days you read 461 items, starred 292 items..." The summary continues, but these few numbers give me what I want.
Only 63% of the content I look at is interesting to me. Almost 40% of the content is a waste of my time.
Wow. I thought that this might be the case. Unfortunately I cannot easily measure how much of my time was wasted, because this metric cannot speak to the ease or difficulty with which I glossed over the uninteresting content. It's easy to skip Penny Arcade's news and Megatokyo's rants. It's far more difficult to determine whether I want to read a blog entry without actually reading it.
Now to start pruning my feed list...