For about 1 month we all are seeing dramatic changes in our Google rankings, Link popularity and all. Page rank of websites seems to be changing hourly. If it is 5 now it can be 2 an hour later. Pages seem to go from a first page ranking to a spot on the 100th page.

Webmasters, especially SEOs are really concerned about this change and this can be seen in various Forums. SEO News discusses about this in detail and here are some of the highlights:

Google algorithm changes started in November 2003 with the Florida update, which now ranks as a legendary event in the Webmaster community. Then came updates named Austin, Brandy, Bourbon, and Jagger. Now we are dealing with the BigDaddy! As per SEO news "The algorithm problems seem to fall into 4 categories. There are canonical issues, duplicate content issues, the Sandbox, and supplemental page issues."

1. Canonical Issues:
These occur when a search engine treats www.yourdomain.com, yourdomain.com, and yourdomain.com/index.html all as different websites. When Google does this, it then flags the different copies as duplicate content and penalizes them.

2. The Sandbox:
This has become one of the legends of the search engine world. It appears that websites, or links to them, are "sandboxed" for a period before they are given full rank in the index, kind of like a maturing time.

3. Duplicate Content Issues:
These have become a major issue on the Internet. Because web pages drive search engine rankings, black hat SEOs (search engine optimizers) started duplicating entire sites' content under their own domain name, thereby instantly producing a ton of web pages (an example of this would be to download an Encyclopedia onto your website). As a result of this abuse, Google aggressively attacked duplicate content abusers with their algorithm updates.

4. Supplemental Page Issues:
Webmasters fondly refer to this as Supplemental Hell. This issue has been reported on places like WebmasterWorld for over a year, but a major shake up around February 23rd has led to a huge outcry from the Webmaster community. This recent shakeup was part of the ongoing BigDaddy rollout that should finish this month. This issue is still unclear, but here is what we know. Google has 2 indexes: the Main index that you get when you search, and the Supplemental index that contains pages that are old, no longer active, have received errors, etc. The Supplemental index is a type of graveyard where web pages go when they are no longer deemed active. No one disputes the need for a Supplemental index. The problem, though, is that active, recent, and clean pages have been showing up in the Supplemental index. Like a dungeon, once they go in, they rarely come out. This issue has been reported with a low noise level for over a year, but the recent February upset has led to a lot of discussion around it. There is not a lot we know about this issue, and no one can seem to find a common cause leading to it.

Google updates were once fairly predictable, with monthly updates that Webmasters anticipated with both joy and angst. Google followed a well published algorithm that gave each website a Page Rank, which is a number given to each webpage based on the number and rank of other web pages pointing to it. When someone searches on a term, all of the web pages deemed relevant are then ordered by their Page Rank.

Google uses a number of factors such as keyword density, page titles, meta tags, and header tags to determine which pages are relevant. This original algorithm favored incoming links and the anchor text of them. The more links you got with an anchor text, the better you ranked for that keyword. As Google gained the bulk of internet searches in the early part of the decade, ranking well in their engine became highly coveted. Add to this the release of Google's Adsense program, and it became very lucrative. If a website could rank high for a popular keyword, they could run Google ads under Adsense and split the revenue with Google!