I double-checked on my computer, and my Google search history was cleared. My old tweets were deleted. My Facebook account was secure but, again, there's still plenty of data, such as the ads I've clicked on, which Jumbo isn't able to access and delete. One problem? It didn't delete my Alexa voice history, all of which was still visible inside the Alexa app on my phone.
Jumbo isn't perfect, but for people who don't want to go through thousands of old tweets or don't know how to quickly set Facebook privacy settings, this is a good tool. It's clearly limited by what Facebook and other companies allow you to delete from outside their systems, but it's better than ignoring privacy settings or never clearing your Google Search history in the first place.
Eventually, I'd really like to see this sort of automatic function built into apps made by companies such as Facebook, Twitter, Google, Amazon and Apple that let you completely delete everything that you've ever done on those services at the press of a button.