I see no need to use robots.txt for that. use Google and Bings webmaster tools. Here you have each domain registered  and can submit sitemaps to them for each domain.

If you want to make sure that your sitemaps are not crawled by a bot for a wrong language. I would set it up in the .htaccess to test for the entrance domain and make sure to redirect to the right file. Any bot will enter a site just like a browser so it needs to obey the server. so if the server tells it to go somewhere it will.

the robots.txt can't by it self, do what you want. The server can however. But in my opinion using bing and google webmaster tools should do the trick.

be careful when optimizing for both, you might end up in a situation where it will look like keyword spamming. I personally wouldn't optimize for both in the page title, just the primary. And then optimize for the secondary and the primary one in the H1,H2 to Hwhatever..

You don't want to look like a spammer.

you can't submit a sitemap in GA so I'm guessing you mean GWT

Whether or not you put it in the robots.txt shouldn't be a problem. since in each sitemap, the urls would look something like this:

Sitemap 1:<url><loc>http:/yoursite.coim/somepage.html</loc></url>

Sitemap 2:<url><loc>http:/yoursite.dk/somepage.html</loc></url>

I see no need to filter what sitemap is shown to the crawler. If your .htaccess is set-up to redirect traffic from the TLD (top level domain eg .dk .com ex.) to the correct pages. Then the sitemaps shouldn't be a problem.

The best solution would be: to have a web in web. (a folder for each site on the server) and then have the htaccess redirect to the right folder. in this folder you have a robots.txt and a sitemap for that specific site. that way all your problems will be gone in a jiffy. It will be just like managing different 3 sites. even though it isn't.

I am no ninja with .htaccess files but I understand the technology behind it and know what you can do in them. for a how to do it guide, ask google thats what I allways do when I need to goof around in the htaccess. I hope it made sense.

actually google has the answer, right here: http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=75712

I always try to do what google recommends even though something might work just as well.. just to be on the safe side

Google / Bing will understand that your plural keyword is probably the same. But it will rank you better if you optimize for the exact match key-phrase. So my advise would be to keep focus on the one with the most searches and mention the other a few times. That way you get both, but make sure that the language is something that makes sense and reads well.

yup

If you don't care what tweet the visitor comes from then you can just see it in GA. But if you want to know what specific tweet traffic was generated by, the yes, you need to do something like what the article stated.

You need to build a new url for each tweet or you won't be able to track the specific tweet.

I hope it made sense else ask me to clarify and I'll do so

Both the urls u posted seem identical to me

1. nope

2)since they are both just the original url, yes

3)both the parameters I wrote were examples. you could call the BigBearBunga or whatever you like. Call them whatever makes sence to you

For SEO I would recommend HTML, with the option to download a PDF. That being said you should also consider how much time is wasted on doing it HTML. Can the company earn more money by spending their time on something else? I mean how often do people actually search for a certain dish when they are about to go out for dinner. My bet is that they are more likely to do a search like: "Italian restaurant in downtown Berlin" rather then "Broccoli slightly roasted in white-wine". Do you see what I mean?