I believe it is called "Bud", "Bud Light", etc., while the Czech company uses the "Budweiser" name.
In the US, trademarks only extend as far as someone might be confused by their use. It's not a hard black and white line, but you can use "Word" if you wanted to, in an unrelated industry from Microsoft's, provided that nobody thought that customers might be confused and think that your product was, or was in some way related to, Microsoft's. (Obviously since Microsoft is such a big company and does so much stuff, this might be harder than if they were purely in the word processing business.)
A good example is Apple Records vs Apple Computer Corp. There was a lot of argument that went back and forth as to whether Apple Computers might be confused with Apple Records -- which seemed ridiculous at the time, because why would Apple Computer ever get into the music business? So they worked it out and came to a settlement to stay out of each other's turf. That happens very frequently. (It got interesting when Apple-the-computer-company decided to get into the music business; my understanding is that they made Apple Records an offer they couldn't refuse.)
And given how ubiquitous Microsoft's products are -- love them or hate them -- the breadth of their trademarks are probably not unreasonable. A no-name company ought not be able to assert a trademark with any similar breadth, because there's so little chance of confusion.
Well they are registered in the
So at worst, I would think that Pinterest could continue to operate under the "Pinterest.com" domain name; the challenge would be whether they want to advertise in the European market, which might be prohibited without changing their name.
If the NSA were to require them to install a secret backdoor then the NSA would be compromising the security of all of their government customers because they don't sell two different versions of their software, it is the same for all customers.
Unless the product has been certified for use with classified information, that's not much of an assurance. The government has its own internally-developed tools -- which presumably it has confidence in (SIPRNet, etc.) -- for protecting information that it deems sensitive. The NSA might well decide that subverting a commercial tool is worth the risk of compromising something that's used by the government, but only in relatively trivial ways.
I don't know enough to impugn Zimmerman et al, but I don't think "it's used by the government!" is necessarily a great seal of approval, unless it's a formal certification (e.g. NSA Type 1 listing) saying that it can be used to protect classified information. And I'm not aware of any COTS software products that are on the Type 1 list; the NSA only approves particular hardware implementations (at least that I've seen, though I'm happy to be corrected although I'd be surprised).