CLAIRE'S DIARY

In all the professionals, people used to documenting their days, only one person actually wrote down their narrative - - -  Claire. Claire had a diary in which she recorded the events in her life.

Claire kept a diary, in which she wrote frequently. She wrote down her dreams in it, including the one in which her baby was stolen. After Claire was kidnapped by Ethan, Sawyer made fun of Charlie by mockingly reading an entry that claimed Claire was getting tired of "that has-been rock star." When Charlie read the diary, he saw a packing list for her trip and that she wrote: 

"I realized I really like Charlie. There's something about him that's just so adorable and sweet."

He also saw that she had written down her recurring dreams of a "black rock" (though it appeared to be of an actual black rock, not the ship). After she returned to the survivors' camp, she tried to use it to recover her memories by writing them down, but ultimately got help from Libby to remember what happened to her at the Staff medical station. 

On the page Charlie views before the one that reveals Claire's feelings towards him, the words "I HATE HIM" are mysteriously written on their own, under what appears to be a list of things Claire misses from the outside world. Also on this page is a word or short sentence that is blurred out. 

There are several ways to view the diary. First, it could just be a diary. A memory book of events, feelings, emotions and thoughts by an individual. Second, it could be part of the story engine. Either Claire herself (and her memories) or those words are feeding smoke monsters/island to re-create those events in her life in order to experiment or experience her raw emotions. Some could argue that Claire's own thoughts in her diary are the active island dreams that played out in the series as real life events. Third, the diary could be planted "new" memories to replace her real world experience. She was kidnapped and had severe memory loss (which was convenient plot point). The diary would be a natural way to try to remember her own past. But it could have been a false past. Recall, she went to the same psychic that Eko wandered into researching his miracle woman.  It could have been an elaborate plot or conspiracy to implant suggestions into a person's subconscious then unleash it in a controlled, stressful laboratory environment (the island).

The island was filled with science stations doing research into mind control, mental suggestion and stress observation. Using Claire as a test subject to determine if false diary memories could replace forgotten real ones seems to be on par with the military-industrial background of the Dharma mission.

Did Claire's diary notations have any impact in the series story? She was searching for a new family after her car crash that injured her mother and alienated her sister. Then, in an unlikely scenerio, she found a respected half-brother, Jack, who cared for her and her baby. She also found an unlikely sister in Kate, who helped save Aaron from the island dangers.

Claire's diary could have been the foundation, the heart of the LOST story lines. But there was not enough meat on the bone to carry all the various tangents to make it a credible theory.