Complex sentence: In August 2000, KMGi partnered with Unicast to move from using the interstitial format for its commercials to the superstitial format, which reduced the slow-down effect of browser downloads.
Split into simpler sentences: In August 2000, KMGi announced that it was teaming with Unicast to move from using the interstitial format for its commercials to the superstitial format. That format reduced the slow-down effect of browser downloads.