Steve Gilmer has this to say about Pluck [link]

Where NewsGator embeds itself in Outlook, Pluck commandeers IE. In effect, it’s a Safari RSS play a year early, creating a mail client-like, three-pane interface with search, RSS and Web sharing spaces. Pluck’s business model appears to be a hybrid of Google and Bloglines, a sort of Gmail-for-RSS concoction that depends on a blend of targeted search and community.