Some people who read your piece probably liked it but simply don't know what to say. Do NOT use another author's characters without permission. He or she will probably tell you what you may or may not do with the character. There is an ongoing shared world called Ravenscar that has its own separate mailing list. List members participate by posting activities of one or more attending personae at said party.
Virtual parties are limited to a few days' duration, as determined in advance by the host.
Anyone who wishes is free to join in virtual parties. Rules for participation vary but are usually announced in conjunction with postings of that particular shared-world fluff. If you would like to join in a shared world but don't know whether there are conditions for participation, write one of the participants off-list and ask. He or she can put you in touch with the world coordinator. If you decide to contribute to any shared world, be considerate of your companions in fluffery.