ChessWorld.net, founded in 2000, is an online chess site.In online chess, a rating is just a number. In the professional world (FIDE), ratings unlock lifelong titles. Once you earn a title, you keep it for life (unless revoked for cheating). Here is the ladder every professional player must climb.
The first two steps on the ladder only require you to reach a specific rating threshold in official tournament play. No special tournament performance ("Norms") is required.
To become an IM or GM, a high rating is not enough. You must prove you can perform at that level in high-pressure international tournaments. You need to achieve three "Norms"—a performance rating in a specific tournament that meets strict criteria (playing against other titled players, players from different countries, etc.).
FIDE offers separate titles for women (WCM, WFM, WIM, WGM). The requirements are generally 200 points lower than the open titles (e.g., WGM requires 2300 rating). Note: Women can (and often do) hold the Open titles. Judit Polgar was a GM, not just a WGM.
Recently, FIDE introduced "Arena" titles for online play. These are generally not recognized in the serious over-the-board community and are distinct from the titles listed above.