Doug Kanter wrote:
....
We shall see if this [increased tax revenues] is just a hiccup. People who know what they're talking
about, like Greenspan, often warn about this phenomenon.

Well, in general, it's two closely related phenomena--lower taxes do
tend to spur economic growth and the subsequent growth is largely
responsible for the increase in revenues. How long it lasts depends on
how long the recovery lasts (obviously).

The former "surplus" was fueled almost entirely by the dotcom-led stock
market bubble..