Many a word of thanks for useful information (4)
I believe the answer is:
data
'useful information' is the definition.
'data' can be an answer for 'information' (data are bits of information). I'm unsure of the 'useful' bit.
'many a word of thanks' is the wordplay.
'many' becomes 'd' ().
'word of thanks' becomes 'ta' (informal way of saying thank you).
'd'+'a'+'ta'='DATA'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for data that I've seen before include "Information for/from computer" , "Facts - Star Trek android" , "Series of measurements" , "Collection of bits of information" , "Collection of items of information" .)