i do free directory submission daily but i get my rank in alexa is varying . whats is the reason ? some times i didnt do seo process ,at that time its show positive rank .. some time i do blog posting directory submission ,at that time rang show negative .. why ??
Alexa rank is determined according to visitors that have Alexa toolbar installed. Since many people don't have it installed and even more people even do not know what Alexa is - this rank is almost useless and often fluctuates for no reason. Don't bother too much about its value - this is a very rough approximation of your real traffic and it is nothing to do with your profits anyway. If you want to know for sure who are your visitors and how many traffic do you gain, analyze your server-side logs instead.
May be the reason behind this your ongoing seo optimization activities which you are applying for the optimization of the website among main search engines.
This info is usually available from your web-hosting admin panel. Look for AWStats or Webalizer keywords. You can also download them via ftp to analyze locally with some log analyzer tool. You should contact your hosting provider to learn is it possible to download the access logs via ftp.