If you remember the previous username, its easy enough to figure out how many posts were made under that identity; just go to
Search (as linked in the header of every page, BTW), and do a "Search for Author". Be sure to set "Display results as" to "Posts"
BTW, "Gezzy" had close to 3000 posts. Looks like she was last seen in the hot tub at a party somebody threw for me. Hmmmmmm .....