Why all wordpress comments are going to spam? I didn't installed any plugins to protect blog from comment and trackback spam.
Please help me to find a solution.
You should not add http:// or wwww. to your Comment Moderation or Blacklist boxes. This will send all comments to a pending status, or WP removes them.
If you want stuff to be blacklisted that contains a certain url, add a fully qualified domain name.
I personally feel that its just coz you may have put some links in beginning in your comments, and they were marked as spam. Ask the blog owner to restore your comments.
I also got the same problem when i use to comment on other blogs for the promotion of my blog and to overcome i stopped commenting for some days. And now its okay.