I found Citynoise through Peter's LiveJournal,
rhodamine, and though I don't remember too clearly, I believe I found Peter's journal through his posts and comments in an LJ community to which we both belonged, 
found_objects. I made a couple of posts at Citynoise myself, many years ago, but slacked off because the posts from other users, and from Peter himself, were so much more interesting than anything I had to contribute. I subscribed to his LJ and found his posts, most of them including photographs, and mostly about his chosen city, New York (I think he was a native of Chattanooga), endlessly fascinating. Peter was a scientist, but also possessed of many other interests, including bicycles, music, art, especially graffiti art, some of which he painted himself, bots, and cats. But his overriding interest was the city, and the ways people use it. His photos of New York, mostly Manhattan and Brooklyn, concentrated on the rough, raw places, such as abandoned buildings, industrial works, and down-at-the-heels neighborhoods. Many of them put me in mind of Edward Hopper, and I often noticed how they depicted the sort of scenes Hopper would probably have painted had he been around in our era. Like Hopper, Peter had a gift for discovering a haunting yet vital beauty in the commonplace scenes of the modern city.
Over the years I followed his journal, Peter posted less and less text, and eventually began making entries that consisted only of photos cross-posted from Citynoise. He last posted about three years ago. As my computer aged I spent less time on other parts of the Internet, and so lost track of him and knew nothing of his illness. Peter suffered from hemochromatosis, a rare condition which causes the cells to store too much iron, leading eventually to organ failure. It is curable if diagnosed early enough, but sadly Peter's condition wasn't discovered until it had proceeded too far, and he died last September at the far too young age of 38.
His friends have posted many tributes to him at Citynoise, and even though I never met him in the non-digital world I wanted to post a tribute to him at LiveJournal. R.I.P., Peter. We will remember you and miss you.