Skype (not exactly web I suppose), Farecast, Hotmail

Seems a pretty naive statement. Especially for someone who has been around HN long enough...

Just this week Microsoft has updated their Azure tools with additional NodeJS support, Python and PHP support.

I know many Java developers that actually thing C# is a better language. Personally, it depends on the platform and tools you want to use. I've written anything from JS to Java to C++ to C# to Erlang to PHP to Python in the last year. I don't care about such things...best tool for the particular job.

But, what do I know...

They had previously acquired Powerset, for one:

http://en.wikipedia.org/wiki/Powerset_%28company%29

Powerset had a ton of hype, then they were acquired and then they seemingly died.

Never heard anything about them since.

I think that technology was rolled into Bing. I don't think they ever expected that it would be a standalone product offering.

Well, there was Hotmail...

Remember Hotmail, for example?

Skype?

They use a lot of Ruby too.

They use a lot of everything because they are huge and they do tons of stuff.