In addition to Stephen's comment, Baidu is little bit insecure.
As SEO concerned, just do everything as you are doing with google and it'll all be fine. Amount of traffic that Baidu and Bing provide versus amount of traffic that google provides is best explained in this picture below.
For December 2012, the search landscape was like this:

- Google: 114.7 billion searches, 65.2% share
- Baidu: 14.5 billion searches, 8.2% share
- Yahoo: 8.6 billion searches, 4.9% share
- Yandex: 4.8 billion searches, 2.8% share
- Microsoft: 4.5 billion searches, 2.5% share
- Others: 28.7 billion searches, 16.3% share