Group is live with revolutionary online content (8)
I believe the answer is:
websites
'online content' is the definition.
(websites are online)
'group is live with revolutionary' is the wordplay.
'group' becomes 'set' (both can mean a collection).
'live' becomes 'be' (synonyms).
'with' becomes 'w' (abbreviation).
'revolutionary' says the letters should be written backwards.
'set'+'is'+'be'+'w'='setisbew'
'setisbew' backwards is 'WEBSITES'.
(Other definitions for websites that I've seen before include "Be wisest about addresses commencing www." , "pages online" , "Groups of connected pages on the World Wide Web" , "Google and Amazon" , "Internet locations" .)