I'll put a cut for those who don't care for more Austen talk, quotes, or more writer speculation.
Near the end of his segment on P&P, Richard Jenkyns, in his A Fine Brush on Ivory, came this bit:
In the last few years sequels to Pride and Prejudice and Emma have been commercially published (as well as a couple of completions of Sanditon). There are also said to be hundreds of Jane Austen sequels posted on the internet. The phenomenon does not seem to occur to the same degree with other classics, however popular--enthusiasts are not constantly speculating what Angel Clair did next, or acclaiming Rodolfo's election to the Academie Francaise--so why does Jane attract this particular kind of homage? What is Elizabeth Bennet doing competing in cyberspace with Buffy Summers?
Daydreaming about the futures of fictional heroines may seem to be sentimental and unsophisticated, but the trouble with dismissing the game to sweepingly is that Jane Austen sometimes indulged in it herself. She wanted her niece Fanny to know that she had spotted a portrait of Mrs. Bingley at an exhibition in London; she was disappointed not to see a picture of Mrs. Darcy either there or at the Royal Academy, but reflected that it would be just like her husband's delicacy to keep it from promiscuous gaze. And in answer to enquiry in the family, she revealed that Mr. Woodhouse died a couple of years after Emma's marriage.
It would be wrong to make much of these private amusements; however, the temptation to treat the characters as real need not be altogether despised or even entirely resisted. We are indeed encouraged to feel that the characters continue to subsist after the book is ended.
The solid substance of her characters also makes it possible to make judgments on them different from those of the author.
It's that last sentence that I find so evocative--and contemplating the tension between it and the phatic elements that draw readers to want to stay and play in a given world.