Yandex (from "index" and the Cyrillic letter Я--in the English transcription, it's supposed to mean "Yet Another Indexer"; in the Russian, "Language Finder") is the Russian equivalent of Google. It provides portal-type services as well as many search functions. Yandex is also an example of Russian e-business becoming successful.
Yandex grew out of Arcadia, an early Russian software developer. It made several search/indexing programs for DOS. Arcadia was swallowed by CompTek, another developer, and in 1996 created several sophisticated algorithms for dictionary searches. CompTek turned this into 2 commercial software products, Yandex.Site and Yandex.Dict, search engine and dictionary respectively. A year later, Runet had grown large enough for a full-featured online search engine, and Yandex.Ru was created. In January 2003, it went public and is currently in good shape.
Yandex has several traits which make it the most sophisticated Russian search engine. One is the use of the dictionary algorithms, which make searching take into account the various grammatical structures of Russian (English-language search engines don't have this problem; Engilsh words barely change at all). Another is uniqueness checking, which makes the engine report only unique documents (a nifty bonus is the display of the server on which the document is on). It also has an on-screen Russian keyboard, a persistent search service, and content filtering. There is also Narod.Ru, a sideproject, which provides a free-webpage service to any 'netizen'.
Its major competitor is Rambler, which is significantly more oriented toward the portal side of things.
Sources? www.yandex.ru, duh.