Many users here defend that links should be opened in the same tab. Many others have a different opinion and would prefer if links are opened in a new tab.
Wouldn't it be a good feature, for the sake of all users, to have a checkbox in the user's preferences/settings asking: Do you want to open links leading outside Stack Overflow in a new tab?
This would make it easier for everybody as users could have an option in this matter.
I know that this has been heavily discussed in the past and that you can easily open links in a new tab (using Ctrl/Mouse Right Button/Mouse-Wheel) but I've not found this feature suggestion and nothing beats one click interaction and freedom of choice.