Some context: The Clinton campaign was a real campaign -- with a war chest and an actual advertising strategy -- for a lot longer than the Trump campaign. The Trump campaign only launched its first TV ad of the general election on Aug. 19. And as much as people talk about "organic" social media sharing, a paid-media campaign creates awareness for ads (e.g., you see an ad on TV, then go online to find it and share it) that earned-media-only campaigns can't on their own.
The most-shared Trump ad, according to Unruly, is this untitled video from the Great America PAC, with 49,678 shares.
One possible consolation for Donald Trump: These ads may all be from Camp Clinton, but they're mostly about ... Donald Trump (i.e., they're attack ads that often simply quote Trump's most outrageous soundbites).