What is Google Reader's “Sort by magic”?

Question

In Google Reader you can choose to either sort by newest, oldest, or by "magic". What exactly does this last option mean?

Answer 1

It sorts feed by looking at item you have previously starred, shared or liked.

In simple terms, it ranks the feed items according to your likeness ... your activities like which feeds you check the most and which you haven’t touched help reader decide feed rankings when sorted by magic.

More info here;

http://www.gtricks.com/google-reader-tricks/what-is-sort-by-magic-in-google-reader/

hope this helps.