I’ve only tried three dedicated writing sites. WhatPad was ok, but only geared to quite short stories. Writers café seemed little used and the third I dont remember , havn’t been for ages.

The sites I did get response from were actually small blog sites, some from the users there, but mainly from their visitors.

Baordforus.com and Blogster.com. It takes a little while for this type of site to get used to you, but they are nice communities.