Here's one take on her testimony:
Rachel Jeantel was a train wreck as a witness. She did not help the state's case. She exposed the manipulations of Team Crump. She was impeached on a few significant matters (see below the fold.) And she admitted multiple lies. It was cringe-worthy but you couldn't take your eyes off it.
Most strikingly, she made Trayvon Martin out to be the profiler of Zimmerman. She said (on direct exam no less by the prosecutor) that shortly after first spotting Zimmerman, Martin described Zimmerman to her as a "Crazy-a*s Cracker" and later, described Zimmerman a few times as "this ni*ga" (as in this ni*ga following him.)
At her deposition, she couldn't identify Trayvon as the person crying out for help. Today, she tried to deny it, but when impeached with the transcript, admitted she told the defense, "It could be, like I said, I don't know. He has a baby voice some days, you know it's not."
Her answer to why she didn't tell the police about her being the last one to speak with Trayvon was laugh-out loud funny: "They said they got the guy, I thought they were supposed to call me." [More...]
She doesn't watch the news, she had no idea Trayvon really died until Tuesday, when a friend sent her a text of an article mentioning his name. Until then, she thought the rumors at school were just rumors. She didn't know as of March 18 when Tracy Martin first called her that GZ had not been arrested. She didn't know about any protests or media coverage because she doesn't watch the news (only occasionally the weather.)
It goes on.
Someone in the Talkleft forums pointed out that she sent at least one tweet about CNN and HLN, in regards to the Z/T affair, though it was apparently long after the shooting.
With the time he's had to prepare, the defense attorney could really hammer her tomorrow.