To my mind there is a difference. You can work towards a goal that you want to reach/achieve, but you can’t work to a goal. I have actually found a couple of examples when googling with “work to a goal”, but to my ears that sounds strange. And you can work (in order) to make a living, but if you’re working towards making a living then you’re still not actually making a living. So "Social media is a good place for people to work towards satisfying their own vanity." makes sense to me whereas "Social media is a good place for people to work to satisfy their own vanity." doesn't make sense to me.