Using same keywords in excess in a webpage is known as keyword stuffing.
2-keyword density :-
Keyword density is a ratio of the number of times a word appears in a webpage to the total number of words in that page.
3-Crawl frequency :-
Crawl frequency refers to the number of times or the frequency of the search engine crawlers crawling a website. A website which is updated frequently is likely to be crawled more frequently with respect to a website updated rarely. You cannot determine when the crawlers will crawl the website next time, so you can use Fetch as Google option in Google webmaster to let crawlers now that you have updated content on the site.
It is the extent up to which a crawler indexes a website. A website contains multiple pages and a page which occurs at the lower side of this page-hierarchy will have little chance of getting indexed.
5-Block comment spam:-
Blog comment spam is spamming by commenting irrelevant or copied content, posting promotional text or links in the comments of the blog. Any blog which automatically approves the comments posted by the visitors are the target of blog spammers.
It is the process of converting the similar URL of a website to a standard or canonical form. E.g. whenever a user types- example.com or http://www.example.com, both redirect to the standard URL- http://www.example.com.
Traffic refers to the number of users visiting the website. The traffic may be organic or paid. Organic traffic refers to visitor coming from clicking on link on search result page. Paid traffic means visitors comes from an ad displayed on SERP. Traffic to a website may also come from referral sites-Facebook, twitter, etc.
It is a text file also known as robot exclusion protocol which is uploaded on root directory of site. This file tell the google crawler which file or folder or webpage are not to be crawled or indexed.
Sitemap is an XML file that contains all the URLs of the website. Along with that is also contain the priority of that particular url how often it will be changed or modified. This file help to locate and crawl all the URLs of the site easily .
Page rank is a ranking of page on search engine with the help of linking algorithm.