Be very careful when approached by strangers asking for direction or offering sexual or massage service.
I just experienced what I had read about scammers on various travel books and also on this informative website 'Tripadvisor'.
I was walking along East Nanjing Road recently in December 2013 and I was approached 4 times within a short distance of around 50 metre.
First, out of nowhere in the midst of crowd, 3 ladies approached me and asked me how to go to Yuyuang Road. They told me that they were tourist from another province of China. I spoke to them for a few minutes. They insisted to make friends with me. I rejected and walked off quickly.
Few steps away, I was approached by a single lady who asked me the same question as above.
Subsequently, few steps down the road, I was approached by 2 different ladies offering to give massage service.
If you are a single man walking there, likely you would be targeted.