Back to back blogs on similar topics.  This again deals with the events of Supergirl #17 where Wonder Woman has decided that she needs to stop Supergirl in whatever way that she can.  There is an interesting bit of comics history here involving the two.  Wonder Woman was one of the last DC characters to get a silver age rewrite as her getting with the times lasted well passed the era of the focus of science fiction on DC characters (so much so that in her revamp they skipped that and went straight to Kung Fu expert mod girl).  When Barry Allen and Hal Jordan were already setting the scene for a new focus on sci-fi, Wonder Woman was still pining over Steve Trevor.  In the same month that Barry Allen made his debut in Showcase #4 (which many say is the birth of the silver age) Wonder Woman was in #109 of her first series where a de-aged Wonder Woman (the first Wonder Girl) had to battle giants that were shooting firecrackers at Paradise Island.  There was an attempt to reboot the character in Wonder Woman #158, but this was seemingly an attempt by Kanigher to keep his job despite the Wonder family dominating the stories for the previous few years.  The character was modernized to a degree, but no real change really occurred until Kanigher left.  The mod girl years signaled the beginning of a new character, still based in myth, but also with a modern outlook and one that would interact with other characters from the DC universe.  A little forgotten story though between Kanigher and the mod girl years (which lasted only two issues) was where she and Supergirl got sent to space to compete in some gladiatorial combat.  So essentially that is to say that once it was decided to go ahead with incorporating Wonder Woman into the mainstream DC Universe in her own title, the first character they decided to do this with was Supergirl.  The two are in some cases a natural fit as they are similar in powers and even in their outlook.  Generally speaking though the partnership between the two has never really occurred.  They have mostly only ever joined forces as part of a bigger group or when there has been some large crisis.  The events of Supergirl #17 highlight this somewhat as the characters are interacting together for the first time in the new 52.  I still don't really see the reason why they have been kept apart for so many years though, even when Wonder Woman interacts all the time with Supergirl's cousin.