Life Outside the Pages

I've been thinking a little bit about characters who live outside of their own world. Writing content for toys is a prime example. I see how characters live in their worlds on television. Then I translate who they are and what they say into a fuzzy toy that comes alive in a child's living room.
And I recently learned that a writing colleague of mine has started a blog. Not a surprise. But he started a blog from the POV of one of his secondary characters, a very humorous and endearing character, who is crucial to his story and now has a voice in the real world.
I was at Carnegie Hall on the infamous evening that JK Rowling announced that a beloved character in her wizarding world, Albus Dumbledore, is gay. And, in response to her rabid, obsessive fans, she relayed where she thought all of her characters may have ended up some 15 years later. None of this explained in her books and existing well beyond the 6,000 or so pages of her amazingly successful series.
And one of my favorite characters of all time, Mary Richards (of the Mary Tyler Moore Show), has her own Wikipedia page!
It got me to thinking about how important it is for me to understand who the characters in my novel are beyond just the pages I am writing. What they did right before the first word was written and where they might be twenty years after they live and breathe in the last word I write. How crucial it all is the writing process.
So, what can we do to extend our characters' lives beyond the page and share it with others? It's very exciting to be able to bring them to life in creative ways. Not just with merchandise (movies, toys, clothes, costumes, and websites) but how else? Just something to think about...because some characters we just shouldn't let die.