The writer and comedian Megan Koester got her first writing job, reviewing internet pornography, from a Craigslist ad she responded to more than 15 years ago. Several years after that, she used the listings website to find the rent-controlled apartment where she still lives today. When she wanted to buy property, she scrolled through Craigslist and found a parcel of land in the Mojave Desert. She built a dwelling on it (never mind that she’d later discover it was unpermitted) and furnished it entirely with finds from Craigslist’s free section, right down to the laminate flooring, which had previously been used by a production company. “There’s so many elements of my life that are suffused with Craigslist,” says Koester, 42, whose Instagram account is dedicated, at least in part, to cataloging screenshots of what she has dubbed “harrowing images” from the site’s free section; on the day we speak, she’s wearing a cashmere sweater that cost her nothing, besides the faith it took to respond to an ad with no pictures. “I’m ride or die.” …