Targeted ads can be annoying, but they're much worse when they're insensitive to tragedies in your life. If you lose a child, seeing ads for children's products is understandably traumatic. Facebook wants to change this. It's testing a feature that lets you hide potentially upsetting ads. The option is currently restricted to blocking ads for alcohol and parenting products, but the social network tells Ad Age that it may add other topics if users report concerns.