They yield short-term interest, showing edge in record time (8)
I believe the answer is:
ephemera
'they yield short-term interest' is the definition.
'edge in record time' is the wordplay.
'edge' becomes 'hem' (I've seen this before).
'in' means one lot of letters goes inside another.
'record' becomes 'ep'.
'time' becomes 'era' (I've seen this before**).
'ep'+'era'='epera'
'hem' placed into 'epera' is 'EPHEMERA'.
'showing' acts as a link.
(Other definitions for ephemera that I've seen before include "Passing items" , "of short span" , "Things lasting only briefly" , "Things that last a very short time" , "Insect with wings" .)