Start with YouTube, but subtract the music videos, the unbridled exhibitionism, the weird, the lewd, the talented and the talentless. Screen the rest for national-security breaches and vulgarity and what are you left with? TroopTube: the Pentagon's new video site launched mainly for service members and their families. In the first 24 hours after it went live last week, 500 videos were uploaded, including "Wives Shout-Out to the Third Brigade A-Troop 133 Cavalry" (8,918 hits as of Nov. 14) and an action clip of a military mom and her baby titled "Scout Poops" (21 hits). Don't expect to find any LonelyGirl15s. TroopTube's closest thing to a video gone viral is Gen. David Petraeus's salute to the soldiers ("You really are the new greatest generation"), which is up to 20,000 hits.