What was the "Mississippi Bubble"?

I've seen references to this past financial mania over the years, but never really understood how it worked or why it was important. But there's a good article on it on, of all places, the Upton Tea Import site. It begins thus:

"When John Law plied his financial wizardry in eighteenth century France, dissolving the national debt and creating fortunes for anyone who invested in his scheme, the rest of Europe looked on in envy. Known as the Mississippi Bubble, Law’s complex manipulations of shares and dividends would eventually destroy the entire banking system that he helped establish. In an effort to copy France’s early success, England created a similar scheme under the auspices of the South Sea Company. When both bubbles burst simultaneously, the ensuing financial disaster evaporated fortunes overnight and sparked bank runs. But, unlike the Royal Bank of France, the Bank of England had avoided entanglement with the speculative frenzy and was able to survive the onslaught. The contrast ensured that Great Britain, rather than France, would lead Europe’s drive toward global expansion and international trade."

The end of the bubble was dire. From another source:

Confidence in the value of Compagnie shares and particularly paper money was now completely destroyed.

On 1 June the law against possession of coins of more than 500 livres was abolished. The 2600 mln livres of bank notes of the Banque Royale were to be withdrawn and exchanged for 250 mln livres of new notes secured by revenues of the city of Paris with 2 1/2 percent interest. On 10 June the Banque Royale re-opened for business, ready to redeem notes. Frantic scenes in front of the bank continued well into July as many converted their notes into coin.

The edict of 15 August 1720 declared the all large denomination bank notes (1,000-10,000 livres) were no longer eligible for payments, except for the purchase of annuities and bank accounts or for the payment of installments still due on the shares of the Compagnie. An October 1720 edict declared all bank notes to be deprived of value after November. All activities and privileges of the Compagnie were taken from it, reducing it to a mere private company. At the end of 1720 Law’s enemies confiscated two-thirds of the Compagnie shares outstanding. His experiment had reached its end.