Someone posting on social media is quaint, taking the lead with hesitation (7)
I believe the answer is:
tweeter
'someone posting on social media' is the definition.
I can't judge whether this defines the answer.
'quaint taking the lead with hesitation' is the wordplay.
'quaint' becomes 'twee' (both can mean sentimental or old-fashioned).
'the lead' indicates taking the first letters.
'with' is a charade indicator (letters next to each other).
'hesitation' becomes 'er' (sound made while hesitating - um, er).
The initial letter of 'taking' is 't'.
'twee'+'t'+'er'='TWEETER'
'is' is the link.
Can you help me to learn more?
(Other definitions for tweeter that I've seen before include "one sending message?" , "One relaying notes" , "Poster of short message - little bird?" , "Message sender" , "One may follow another" .)