The advent of these so called social web 2.0 websites is really a descriptive term for a more modern website where the involvement of the public is on a daily basis.
With this website model I propose that there is a great big hole in the niche side of it all. There are so man6y bookmarking sites but they all cover the entire internet and are not generally tied to a single niche. The are some in the internet marketing side of things, but I am talking about a smaller more focused website like one that only bookmark articles or reports written by doctors, or one that does the same but is restricted to resort owners.
This site would NOT be a forum for resort owners but the members would have to own a website that promotes resorts or hotels and then they would be able to bookmark reports or events or even just a new price special on your website. Sometimes your website would be very well placed on the SERPS (search engine results pages) and more and more hotel owners would use you to "announce" their new tariffs.
Can you see the benefit of starting up a socially active website that only caters to a specific portion or niche? You could add other features that would be a bonus to your members that would allow them to have a second feature wheree they can do one of those short 140 character type message blasts that would get their new bookmarked even sooner. The big search engine spiders would be regular visitors to this type of website because it would be very active and your detail would be noticed quickly.
If you look through the different types of website models that I have written about you will notice that a lot of them could be intermingled, for example this type that I am writing about here could be changed into a membership type of website. What you would do is have different levels of participation that would be allowed firstly for free and then later for increasing levels of payment. So for example a free member could bookmark as often as they like, but a level one member would gain a personal page with linking allowed. This would keep stepping up to where a level three member would be allowed to have 10 profiles and all the other benefits that go with it, the message broadcasting and pages, forums and the whole package.
I do suggest though that you get the basics of the website planned out correctly from the very beginning as you will find it very difficult to change complete layouts later down the line. People are never happy with change and you could lose members fast if you keep changing the structure of your website. Pay a good website designer to do all the planned aspects into your site before you even think of launching.
I do believe that you could have a winning website here with this model. Have fun.