One of the marketing slogans of RSF, emphasising the power of IKAT to generate "correct" markup in one quick pass, even in complex portlet/integration scenarios. This is in contrast to many "transform" based solutions such as SiteMesh or, indeed, WSRP itself, which consider a once-rendered web-page as ripe pickings for picking over again in the hopes of finding URLs, CSSs or other tasty tidbits to be reprocessed.
RightFirstTime is enabled in RSF firstly, by means of the IKAT ViewTemplate system, and has the fine details taken care of by the StaticComponentRenderer architecture, whereby small request-specific rendering components are Spring configured into the view pipeline as request beans.
In the words of Dr. Johnson[1], "To render a web page twice is like fitting wheels to a tomato -- time consuming, and completely unnecessary".
[#1] NOT[2]
[#2] Script