I really want to know how Google declare SPAM to a website.
Can anyone explain? Also how to check a website is SPAMMED by Google?
example of spam is when you submit your link to a blog commit and it has no purpose to the subject. You should never make a commit like " nice post" and then leave your link, that is spam.
If you mean how does Google decide that an entire site is simply spam, then this link might help: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=40052
According to that article, Google will alert you through Webmaster Tools if it decides your site does not meet its quality guidelines.
A website can be considered as spam if it has scraped content. Scraped contents are those stolen from other source either through copy-paste or the use of software. Wikipedia is one of the common source of these scraped content. If your website contains too many keywords or keyword phrases, then it can be considered spam too. The keywords should be placed in the content in a most natural way and avoid too many repetitions too. Hidden text is also another form of spamming. Texts are usually of the same color with the background, these invisible words are usually keywords.
If you are doing this then you are doing spamming.