<p>Codeforces (http://codeforces.com) is a programming competition platform that also serves as a hub for the competitive community. On Сodeforces, we’re not just holding periodic open international tournaments - we’re also a social network of people interested in competitive programming.</p><p>Main functions:  open online competitions  members’ live rating  problem archives (from past contests)  practice section AKA “Gym”, in which you can participate in so-called “virtual contests” where your submissions are merged with timeline of one of the past contests, or create your own contest  problems with precise and fuzzy solutions  branded activities/competitions for sponsored events  social platform including blogs, comments, votes for the blogs / comments, personal messages  multi-stage competitions with qualifying round(s) and the finals.</p><p>The website was launched at the beginning of 2010 and quickly gathered a loyal following. The number of registered users is constantly increasing, so in May of 2013 community has slightly more than 100000 registered users. A year ago, there were about 52000 users, and two years ago - about 18000.</p><p>Number of people, to the beginning of the year 2013</p><p>Regular programming contests held on Codeforces are open to all registered users. Users acquire rating points based on the results of those contests, and contests are divided into 2 groups - less complex and more complex. Participant’s current rating will determine the division he’s able to compete within. Problems are algorithmic in nature, solving them requires the ability to think and to program an efficient algorithm. The judging system is fully automated, participants receive a verdict shortly (depends on the load, but usually about a minute) after submitting the solution. We conduct about 4-6 regular contests per month, each contest consists of about 5 problems.</p><p>You can use various metrics to measure the popularity of Codeforces, but if you take into account only the users that participated in at least one competition during the past 6 months, you’ll get the very impressive number - 13000.</p><p>All of the problems from the past competitions are available for the participants to practice on. In addition, there’s a dedicated section “Codeforces Gym”, in which participants, administration, or teachers can create contests to practice on.</p>