Online design discussion sites are a popular networking platform drawing thousands of designers from all around the globe. These sites show promise as emerging design resource by enabling designers to learn about design techniques and tools, share ideas and to seek (receive) critique to help refine their ideas, and to learn from other designers' experience. In this paper, we report results of a study that aims to understand designers' experience and activities in online design discussion site and how they relate to design. We have analyzed member profiles (N=12164), posts submitted by one-time posters (N=2854), and post-contents (N=1004) for a month and conducted follow-up interviews (N=5) to investigate what roles such sites play in supporting design. Our findings reveal that while designers find such sites extremely promising, ineffective representation of ongoing activities, lack of visibility of contribution, and difficulty in finding needed information hinder (even discourage) participation. We propose actionable implications that can lead into better site design.