Strategy: Limit The New, Not The Old
One of the most popular and effective scalability strategies is to impose limits (GAE Quotas, Fotolog, Facebook) as a means of protecting a website against service destroying traffic spikes. Twitter will reportedly limit the number followers to 2,000 in order to thwart follow spam. This may also allow Twitter to make some bank by going freemium and charging for adding more followers.
Agree or disagree with Twitter's strategies, the more interesting aspect for me is how do you introduce new policies into an already established ecosystem?
One approach is the big bang. Introduce all changes at once and let everyone adjust. If users don't like it they can move on. The hope is, however, most users won't be impacted by the changes and that those who are will understand it's all for the greater good of their beloved service. Casualties are assumed, but the damage will probably be minor.
Now in Twitter's case the people with the most followers tend to be opinion leaders who shape much of the blognet echo chamber. Pissing these people off may not be your best bet.
What to do? Shegeeks.net makes a great proposal: Limit The New, Not The Old. The idea is to only impose the limits on new accounts, not the old. Old people are happy and new people understand what they are getting into.
The reason I like this suggestion so much is that it has deep historical roots, all the way back to the fall of the Roman republic and the rise of the empire due to the agrarian reforms laws passed in 133BC. In ancient Rome property and power, as they tend to do, became concentrated in the hands of a few wealthy land owners. Let's call them the nobility. The greatness that was Rome was founded on a agrarian society. People made modest livings on small farms. As power concentrated small farmers were kicked of the land and forced to move to the city. Slaves worked the land while citizens remained unemployed. And cities were no place to make a life. Civil strife broke out. Pliny said that "it was the large estates which destroyed Italy."
To redress the imbalance and reestablish traditional virtuous Roman character, "In 133 BC, Tiberius Sempronius Gracchus, the plebeian tribune, passed a series of laws attempting to reform the agrarian land laws; the laws limited the amount of public land one person could control, reclaimed public lands held in excess of this, and attempted to redistribute the land, for a small rent, to farmers now living in the cities." At this time Rome was a republic. It had a mixed constitution with two consuls at the top, a senate, and tribunes below. Tribunes represented the people.
The agrarian laws passed by Gracchus set off a war between between the nobility and the people. The nobles obviously didn't want to lose their the land and set in motion a struggle eventually leading to the defeat of the people, the fall of the Republic, and the rise of the Empire.
Machiavelli, despite his unpopular press, was a big fan of the republican form of government, and pinpointed the retroactive and punitive nature of the agrarian laws as why the Republic fell. He didn't say reform wasn't needed, but he thought the mistake was in how in how the reform was carried out.
By making the laws retroactive it challenged the existing order. And by making the laws so punitive it made the nobility willing to fight to keep what they already had. This divided the people and caused a class war. In fact, this is the origin in the ex post facto clause in the US Constitution, which says you can't pass a law that with retroactive effect.
Machiavelli suggested the reforms should have been carried out so they only impacted the future. For example, in new conquered lands small farmers would be given more land. In this way the nobility wouldn't be directly challenged, reform could happen slowly over time, and the republic would have been preserved.
Cool parallel, isn't it? Hey, who says there's nothing to learn from history! Let's just hope history doesn't rerepeat itself again.