We all know bing.com is a Microsoft site, hence it's technology is built upon Microsoft stuck (I can hardly imaging something different). Does any one have an idea about what technologies are used in Bing.com (for serving the pages, for indexing the web, for searching the database.. etc)?
/* Strange question you say?! C'mon it's StackOverflow, we can get a good answer ;-) */
Any web search engine uses a web crawler to travel and index web pages and their content. Bing uses a crawler called Msnbot which, in the past, has been often criticized for being too slow.
Msnbot should appear this way in your server's log:
msnbot/2.0b (+http://search.msn.com/msnbot.htm)
Also, Microsoft has a FAQ page about Msnbot.
Java & oracle on linux boxes :)
Seriously, it is asp.net & sql server on windows.