This is quite common but not in competitive keyphrase environments although keywords in domain name is major points.

I think such website with one page and on first page of search results possible through paid software which indexed website to top but i think this is for very short period to time.

Not paid software, just keyphrase rich content, even a one-pager will rank highly for obscure keyphrases.

I think they are just like a long article to explain what type of any specific product is. They have content for that only page.

thanks.

It depend how much time they spend on it

My views on long keyword rich domains names are that you should go for them if you are targeting single products...for example if you target "any green tea product"

but if have wide range of products, you need to have a domain names based on your brand and company name which helps to build brand and long term benefits in google

keep the keywords changing occasionally, keep the keywords for alt text of images tags, by keeping your site in other popular sites as link building, keeping social bookmarking. and frequently changing the data, and posting the paths in forums will help you to SEO.

Page Title is one of the most important thing to consider when doing on-page SEO. It’ll be hard to rank for a certain keyword if it doesn’t exist in your title.

Always make your title short but also a catchy one and must be keyword rich.

Deep Linking is where you link each of your related articles aside from your homepage. This can help your single pages rank much higher for that keyword.

By doing this (linking each of your related articles), search engines will know that you have a lot of good content. That is why, it is not a good idea to always link it to your homepage because search engines will think that you don’t have much content because it always link to your homepage.

hope that will help a little bit!