[David Tan]

Everytime they make it stricter, web publishers have to work harder. It's not about so much about changing the algorithm but more about Google creating more and more rules about what not to do.

Google will then shape the look of the internet, how websites will be designed, how content will be wrtitten, who sites will link to each other, etc.

It's their search engine. It looks like by imposing more and more limits and requirements that need not apply to their own services, they will edge out adoption of competitor's services and encourage more advertisers, businesses to utilize google's.

Soon, the only way to effectively get traffic from google is to use their services. The question is... Why don't they just impose all the limits at one shot and make this rule in effect right away?

By slowly imposing the limits, it allows time for publishers, merchants to adopt their services and begin to rely on it. Once it helps generate revenue/income consistently, leaving it would create a big hole in your revenue/income level. So you keep on using it. Then slowly, more limits are imposed and google's services becomes more effective while the competitors' services becomes less so. Google lures you in and keeps you there rather than frighten everyone to Yahoo.