If you want to pick the closest hero, you will have to use a trigger to do that. There may be some triggers in the Tutorials and Resources section that will pick the closest unit or so that you can use to do that. Then once you have the right unit, it will be a simple matter of ordering your goblin to use the Kaboom ability on the unit.
i'd say the easiest way would be to just create the goblin and let him auto-attack an enemy.
by default the wc3 standard unit ai will order your goblin to attack the closest enemy in range.
you will then only need to issue the order to use kaboom once a goblin attacks a unit.
I am working on getting access to the old news portal under a different URL for those that would rather use that for news before we get a different news view.
It is OK though for the main page to open up on the forum in the view it was before. As long as the portal has its own URL so it can be viewed that way I do want to try it as a regular forum view for a while
I switched it to a "Standard" article forum. This will show the thread list like normal, but the threads themselves will have the first post set up above the rest of the "comments"