Remote OK is on of the largest and most popular remote job boards in the world, created by Nomad List founder, Pieter Levels in 2015. They share their site traffic publicly, and get 600-800k visitors per month.
The site's wide reach alone makes it a popular choice for employers hiring remotely. Where the site falls behind, however, is in its complete disregard for user experience and design.
We Work Remotely is a Canadian remote job board and one of the largest remote work job boards in the world. Founded in 2011, they're well-established with some great companies using the site regularly. We Work Remotely is owned by Tiny Capital.
The site is relatively easy-to-use but has some issues and makes a few confusing claims (we'll get into those). They have hundreds of remote jobs from companies all around the world. For job seekers, they've recently introduced well-overdue update to their search functionality called advanced job search. This allows job seekers to filter jobs by keywords, basic categories, companies, and time zones.