I've studied the duplicate content / syndication effect very heavily (LoL, thats what I do). Unfortunately posting here on Biznik and also on your own site for people without well-established sites is problematic.
I can do so simply because my site has as much weight as Biznik. That allows me to not worry as heavily about duplicate penalties on my site.
For a new site, having duplicate penalty can drown it's rating very quickly. Just like the secondary index, Google can label your site as a syndication site even if it is the original.
I would recommend that unless you know what you are doing and where / how your current site ranks, to not post duplicate content on another site such as Biznik. It should be original to prevent from submarining your efforts.
Dan- I would say that Biznik should have an "original work" policy. Otherwise syndicating a site may eventually get them listed in the search engines as being a spam syndication site.
Biznik is somewhat protected from this, as 99% of what is on the site has been original. That track record helps a lot.
If your site is under six months old, you should not duplicate content on other sites or you risk doing some bad things to yourself.