If this was known years ago, why are they telling us now?

W.H. dispatches Gates, Clinton to talk Iran on Sunday talk shows
The White House is sending Secretary of State Hillary Clinton and Defense Secretary Robert Gates to do the Sunday talk shows, sources say, and the topic will be today's Iran nuclear revelations.
"It's no coincidence they're all pre-taping today," an administration official told POLITICO.
Another administration official told POLITICO Obama's announcement today from Pittsburgh on the previously undisclosed Iranian clandestine enrichment facility "came together quickly" prompted by an Iranian letter to the UN atomic watchdog body.
The IAEA confirmed today that it had received a letter from Iran September 21, in which it admitted construction of a second enrichment facility. The IAEA announcement was rushed out just before Obama, France's Nicolas Sarkozy and the UK's Gordon Brown issued an announcement on the Qom facility from Pittsburgh before heading into G-20 economic talks.
A diplomatic source told POLITICO that the facility built into a mountain near Qom Iran dates back to 2005, but western intelligence agencies did not know of it until some unspecified time much later.
Administration guidance issued after Obama's announcement says the U.S. has been aware of the Qom facility for several years. (POLITICO)