Are all segments created equal?
 

Are all segments at least worth 1 segment point if they are booked on CO.com? I don't understand how some CO codeshare earn are at 50% elite mileage and others are at 100%. And does a 50% elite credit codeshare flight count as one segement?

Only certain classes earn segments, even if booked online. You'll get full EQM regardless of class if booked online, but no segments unless it's one of the higher classes. As for a codeshare it depends on the airline being flown and what booking class it is booked in by the ticketing airline.

To get 100% EQM and segment credit for your discounted flight you have to not only book on CO.com but you have to make sure that the outside of the plane you are flying on says "Continental" (ie you're not codeshared to someone else).