Microsoft is releasing Windows in Welsh and gets some props for championing linguistic diversity (Catalan and Tamil are also on the list). Ernest Miller's not impressed, and neither am I. Catalan and Tamil are spoken by huge populations with considerable political heft; it's not like they're dying languages! What's more, both languages are major points of ethnic identification for their speakers. From a business standpoint, this is the only thing to do.
The best that can be said is that they're getting more sensitive to local culture after the inept way in which they handled the situation with Hangul in South Korea. In that case, they tried to take over the local word processing software in order to replace it with Microsoft Word, adapted for Korean. But the Korean alphabet, which is also known as Hangul, is a point of tremendous national pride in Korea, to the point where they have a national holiday to celebrate it. Because of Hangul's complexity, the Hangul program was seen as something of a miracle, and Microsoft's attempt to replace it led the public to rally around their local product. Eventually the takeover bid failed, severely damaging Microsoft's Korean reputation in the process.
The point here is that taking local cultural and political realities into account can be good business, and that's what's going on with Windows in Tamil or Welsh. When they put it in Lakota or Jaqaru, then we can talk about linguistic diversity...
By the way, I wouldn't waste a lot of time worrying about whether Microsoft is going to be the arbiter of language prestige in the near future. The availability of internet content is way more important to that, and unless they can develop a dominant search engine, Microsoft won't have much effect there.