Online product manager
Caring. Also, the ability to parse out the crux of the problem out of a deluge of feedback.
Working with a team to understand complex problems and solve them in a simple, elegant fashion. Making people feel smart when they use (our) products.
Nothing, but what I find a challenge most often is the shifting nature of the role of a product manager - everyone has a different idea of what it is that product manager should 'own' in a company.