Energy firm keeping trademarks present in group of posters (11)
I believe the answer is:
blogosphere
'group of posters' is the definition.
(people posting online)
'energy firm keeping trademarks present' is the wordplay.
'energy firm' becomes 'BP' (British Petroleum).
'keeping' is an insertion indicator (some letters kept inside).
'trademarks' becomes 'logos' (logo is a kind of trademark).
'present' becomes 'here' (both can mean in attendance).
'bp' placed around 'logos' is 'blogosp'.
'blogosp'+'here'='BLOGOSPHERE'
'in' is the link.
(Other definitions for blogosphere that I've seen before include "modern postal area" , "field offering many views" , "part of internet" .)