Managing Change
Those that have been around a while will tell you, if you don’t like the way things are on the Internet, just wait a few days… it’ll change. Actually, it changes more often than that. Google makes upwards of 500 changes per year to their algorithm alone. Services come and go, as do the companies that would make use of them; what works best for rankings changes periodically; what’s acceptable and unacceptable by the search engines’ standards varies and the shiny object that seems to grab nearly everyone’s attention can change as quickly as the tide.
With all that said, though, the changes that take place in terms of what does and doesn’t work in optimization are typically not major. More often than not, they simply involve a bit more emphasis here, a bit less there.