I'm surprised American network has strange content (6)
I believe the answer is:
crumbs
'i'm surprised' is the definition.
(expression of surprise)
'american network has strange content' is the wordplay.
'american network' becomes 'cbs' (American TV network).
'has' means one lot of letters goes inside another.
'strange content' becomes 'rum' (I can't explain this - if you can you should give a lot more credence to this answer).
'cbs' going around 'rum' is 'CRUMBS'.
(Other definitions for crumbs that I've seen before include "Surprised expression; bread fragments" , "Little things offering minimal comfort" , "Crikey, cripes" , "Small bread particles" , "that surprises me!" .)