I am going for "this keyword" and thiskeyword.com as well as this-keyword.com are both taken. However, 'this--keyword.com' is available. thoughts?
Yes, I would really advise against doing that. As mentioned most people don't remember dashes let alone two of them. And like waffles stated how would you tell the URL of your website to someone. e.g. "Yea you can check out my site. It's www...travel..hyphen..hyphen" "2 hyphens?" "Yup, dot com." So go with the keywordonline.com as stated or maybe look into brandin if it is appropriate (i.e. google, mozilla, gibberish names). Skinny Skinny
I have noticed on other sites that the word--word.com is being heavily traded, cant see a use for them at all.
No - two hyphens together look cheap. There must be other ways to describe the sites' business in a domain name without the hyphens. Plus if word1word2.com and word1-word2.com are already taken, you will lose a lot of visitors to them.