On topic, good target's for spy's include galactic wonder's, the various capital's, and of course any revenue generating improvement's.
Well, it depends. Often just putting a spy on one manufacturing square will do more than putting it on the manu cap. Same with research. You have to look at the stats before and after.
As to those who are hijacking this thread, at the risk of drawing flame-fire, the internet, and hence forums, are not the same thing as the printed word. And they're also international, which is actually a good thing. I'd rather hear from someone in Germany or Romania, or China, in poor English, than to have those people scared off by fraktard anal "grammarians." Which grammarians, by the way, when push comes to shove, probably only know grammar by way of instinct. If there's a "real" grammar expert in these forums, he probably knows enough to realize that forums are quite distinct from scholarly writings, or even newspapers.
OK, flame away, FRAKTARDS!!!!!!!!!!