What do you say about of setting up a social bookmarking place on my website ?

I have a technology blog, forum and classifieds on my domain like:

mydomain.org - blog
mydomain.org/talk/ - forum
mydomain.org/classifieds/ - classifieds

I am planning to set up social bookmarking also on to my website. But i am worrying about of outgoing links of social bookmarking. Will it hurt my website on search-engines anyway?

Should i set up bookmarking section like:

mydomain.org/bookmarks or
bookmarks.mydomain.org

 

If you have have users to use them, yes, create one.

if you worry about OBL very much, just use nofollow

 

but even if we put nofollow, if we use mass amount of out bond links, google will not mind the "nofollow" tag right ?

 

I think , mydomain.org/bookmarks this is good

 

i want to know, if i setup a social bookmarking system on my website, will it loose my rankings coz of huge outbond links ?

expecting your advices.