I would think they could sell it a bit better than "Create shared experiences with people you know, and people you want to know." The point of a one liner is to hook the reader with something unique and memorable--you could transplant this phrase onto half the social startups out there.
Wow, it's always taken me about an hour (sometimes two) to, but 4 is pretty rough. Care to share why this is, and how you combat it? I do the regular stuff, but have also come to embrace it since I often have pretty productive thoughts.