You'll be pleased to hear that you can now search the site by character name. You can either add a specific filter on other searches using the prefix "character:" or just search normally with the character name as a keyword, and the site will now use the character field to help rank the results so that stories where that character has a significant role now appear near the top of the results list.
Also, when browsing categories you can choose to filter the list of stories by the most popular characters within that category.
To provide the data for this feature, the site will now scan each story shortly after it is uploaded and attempt to a) find which words in the story are names of characters and b) determine which of them has the most 'screen time'. It does this by analysing each paragraph of the story and trying to spot who is the primary subject, and then assigning the entire paragraph to that character.
You can see how a particular story has been classified by referring to the new pie chart on the Statistics tab, which shows the top 15 characters that were identified (as long as the accounted for at least 1% of the story). Note, there may up-to a one hour delay between a story being added/updated and the character data being analysed.
This also allows us to answer another long debated question of whether Buffy, Willow or Xander is the most popular character:
you can now see the Top 30 characters accross the whole site on the Miscellanous Site Statistics page.
There is also an author-specific version of this chart on the Profile page that shows the leading characters in an author's stories.