Anti-spam enabled for official website

Hi community,

I keep in mind that our official website should be as free as possible, for example people can leave comments anonymously.

However, this feature became the cat's paw of spam, there are over 50,000 spams arrived in about two weeks.

To deal with this problem, I have:

   * deleted all spams: I'm sorry if I deleted your comments by mistake.

   * enabled an anti-spam module: may ask you to type a captcha, sorry for inconvenient.

^_^