A videochat, these days, means communication between people over the internet, where both participants can see each other on their computer screens. In the early days, chatting on video required installing special software. Now all you need is a browser with a flash player installed and a webcam, which can be bought for very little money (laptops often already have one built in). Sex videochats are the same as regular videochats, except that the main purpose of communication in porn video chats is to get sexual pleasure.
Videochats arrived on the internet as soon as connection speeds allowed enough data throughput for video transmission. By that time, the internet was already being widely used for communication, mostly through text messages. 
Obviously, seeing and hearing the person you're talking to is a lot more interesting than exchanging faceless text, so the idea of video conferencing and videochats was in the air long before it became technically achievable. And like any means suited for spreading information, videochats were quickly put to work for the porn industry. Sadly, unlike ordinary videochats, porn video chats are overwhelmingly paid, which is, generally speaking, typical for this industry. It's not hard to guess that sex videochats began their triumphant march from the stronghold of freedom and democracy — the USA. After that Europe got on board, and around 2007 porn video chats aimed at the Russian audience appeared as well.
Every year new sex videochats pop up all over the world on an almost industrial scale. However, only a handful survive — the market is oversaturated. Russia hasn't been spared from this trend either — in 2009 alone at least 5 new porn video chats appeared on the Russian internet. As of now, all of them have either already given up the ghost or are in their death throes. In 2010, I'd guess, there will be more new Russian sex videochats.
The main trends in porn video chats today are providing high-quality HD video and moving into the mobile device niche. As always, Western sites are leading the way here.
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