While nothing is official yet, the producers of The OC are getting ready for season 4. Creator Josh Schwartz revealed that Marissa's sister Kaitlin will be back next year. In fact, Kaitlin will be moving back to Newport and will attend school there. Schwartz anticipates that there will be a whole new crop of characters and storylines revolving around Kaitlin. Meanwhile, Taylor will be made a series regular as well.
I find this to be good news and I'm glad that the OC has decided to keep some interesting characters around. Season 4 should be an improvement and something to look forward to.