What people complain about that? Other developers or people in tech? Sure it doesn't look as modern by today's standards but is changing the styling, font, etc.

What people complain about that? Other developers or people in tech? Sure it doesn't look as modern by today's standards but is changing the styling, font, etc. going to make it easier to use? Doing so may actually startle a lot of users which is most likely why they have only made small changes over the years. I have seen a lot of CL alternatives that look nicer at first glance but the UI lacks. Sometimes more features is not a good thing. KISS principle is oftentimes better especially when you are working with such a wide user base such as Craigslist. CL only has 30 employees, never took VC, is one of the most highly visited sites and brings in millions of profit a year. Not many other web companies can claim that. If I were in that position, I don't think I would be too worried about the tech community complaining about how ugly my site was especially if my users continued to come back and benefit. CL does have rss feeds (example https://slo.craigslist.org/search/web?format=rss https://slo.craigslist.org/search/web?format=rss) but they have pretty strict terms on how you can use them.