Lawrence O'Donnell had the editor of Radio-Info.com, Tom Taylor, on to discuss this unusual move in the wake of the Sandra Fluke debacle, aka "Slutgate." Taylor sees this as a cooling off period as Premiere Networks plans their next move:

TAYLOR: The whole temperature level of this thing is something that the syndicator and Rush himself would like to bring down. And as you say, that's why Rush had a round of golf today.

via Think Progress:

Radio-Info.com reports that Premiere Networks, which syndicates the Rush Limbaugh show, told its affiliate radio stations that they are suspending national advertising for two weeks. Rush Limbaugh is normally provided to affiliates in exchange for running several minutes of national advertisements provided by Premiere each hour. These ads called “barter spots.” These spots are how Premiere makes its money off of Rush Limbaugh and other shows it syndicates.

But without explanation, Premiere has supended these national advertisements for two weeks. Radio-Info.com calls the move “unusual.” The development suggests that Rush Limbaugh’s incessant sexist attacks on Sandra Fluke have caused severe damage to the show.

From the memo:

Attention Traffic Managers of Premiere News/Talk Affiliates:
We are suspending the requirement to run barter spots for two weeks, March 12th and March 19th, for our News/Talk affiliates only.

Please replace/re-traffic any Premiere barter spots immediately. Contractual requirements to run barter spots are being suspended for these two weeks only. Replace them with Lifelock and Lear Financial or a local spot of your choice.

Think Progress have also reported that 140 sponsors have now requested their ads no longer appear on the Limbaugh Show.