Xomba has reinvented itself, now that Google has started to slap down spam. As a result, you can no longer bookmark your own articles (most of the content Xomba has). Now you can bookmark other people's articles, and stuff you find on the web, or you can write articles for Xomba. Don't try to bookmark your own stuff on Xomba or you will find your account is suspended. (If you don't use the same username, I don't quite know how they can tell, but it's not worth risking your account.)
Xomba has also discontinued referrals for the moment, so as a sweetener, they have increased their Adsense share to 60%.
If you still want to have your articles bookmarked on Xomba, the best way to to that is to set up a randomized ring with at least 50 members, and intersperse those bookmarks with others you find around the Internet (and truthfully, there's nothing easier than bookmarking other people's stuff you like). Setting up a randomized referral ring is tedious and I don't recommend it.
It's easier to subscribe to blogs you enjoy, and bookmark each post on Xomba. Xomba won't let you post duplicate URLs but finding a blog with only a few readers (and preferably not a blog about making money online) won't be a problem. Plus, you'll be paying it forward to your favourite blogger!