The major conflict came out of nowhere. And the subplots? Let me try and summarize just what went on:
(SPOILER)

And that's cliffhanger #1.
Meanwhile.... who snitched the expose? The girls first thought it was Rebecca, erstwhile contravida to Casey, who, in the final episode, is given a few moments to reveal a "nicer" side to her character. Rebecca hooks up with Cappie (Casey's ex), suprisingly.
And that would have to be cliffhanger #2.

Yes, cliffhanger #3, that. Oh and yes, Jen K is played by the famous Youtube celebrity, LonelyGirl15.
Following on her threat, Frannie shakes up Casey's relationship with boyfriend Evan, who eventually dumps her.
That's cliffhanger #4.
And finally, Ashleigh outs Calvin and accidentally reveals to his frat brothers he is gay. -- cliffhanger #5.
See? Was not just too much for one final episode? And the worse part is not knowing what's gonna happen to Casey and Frannie, Casey and Evan, Rusty and Jen K, Rebecca and Cappie, Calvin and everyone else because Season 2 will be back in 2008!!!
For more on Greek, WikiP has a comprehensive guide that's very easy to follow and here's my initial reaction to the show.
[Greek]
----------------
Now watching:
High School Musical 2
Burn Notice Season 1 Episode 10