I think it's fine if you don't put a real picture of yourself.  Some people prefer to remain anonymous on the internet, and that's fine because it only helps you keep you safe from potential stalkers. 

Yes, they both mean the same thing. As the previous answerer said, "sneakers" and American English and "trainers" is British English. However, the most common word in America is "tennis shoes".

Hi there. These are just words turned around backwards to make them more interesting. チャンネー is backwards for 姉ちゃん, and シースー is backwards for 寿司 I'm not sure where this phrase came about, but it seems to be common when going out to sushi somewhere in Tokyo. I did a few internet searches and this was all I could come up with. For example, you might say ザギンでチャンネーとシースー 銀座で姉ちゃんと寿司 Sushi with my sister in Ginza. An internet search also brought up an application on Mixi called チャンネーとシースー, which could be where this phrase comes from, but I'm not sure what the application is for. Hope I could help.

First notebook entry: Introducing myself

Er...I'm a 19-year-old Chinese girl. I'm not good at introducing myself - I totally don't know how to write a self-introduction well haha . My English is not good so I wanna make progress on it.  I hope I can make some friends here!