I think the links should open in the same window (like they do here on HN) instead of in a new tab/window. If I want a separate tab, I can Cmd+click and Browsers don't have the reverse option for opening in the same window.
In general, it's better not to force an action onto users. You might prefer things opening in a new tab, but you always have that option. If it's forced on users, it is frustrating for those who would prefer that not to happen.
That's a good user setting, but as opening in the same tab is the default browser behaviour then it should really stay that way. Opening in a new tab takes control away from the user.