a webpage will distribute its rating (notice i didnt say PR) to all the pages its linking to. For example, a site will benefit more if it is the only site that a high rating page is linking to, as compared to if the site is one of hundreds being linked to by the page. SEO:新站排名不稳定的Google幽灵现象
1) A popular issue and one that is particularly important at this time of the crawl/index build is what Ive come to call Google Ghosts.
Every so often a new site is put up on the internet, or a new page, and it appears in the index before the monthly update. Quite often it has good rankings at that point in time. But horrifyingly they often disappear again a few days or weeks later.
These ghostly appearances are often confusing to newbies, and sometimes to the eXPerts! However, the explanation is quite simple.
Google has two types of crawler, its main crawler and the fresh crawler. The main crawler is capable of discovering new pages. If a new page is discovered immediately after a new index has been built then that pages discovery is of little use if it has to wait a month for a new index to be built.
The building of a new index also contains all the calculations of the non-query dependant factors involved in calculating a pages rank (for example, PageRank).
To fully utilise the pages, without waiting for the next set of index calculations Google must do something very simple. Guess its ranking. By guessing the new content is at least available to the searchers.
