I realise this is the 2nd question I've asked tonight and it's not something I'm thinking of doing but another poster on the forum asked about including emails in a novel and it triggered a thought. (Not a normal occurence sadly!) Has anyone seen an online "novel" written through email and social media such as twitter and facebook etc? I'm thinking an email conversation, hyperlink to a facebook page which references somebodys twitter post etc etc. All done in chronological order and with a viable backstory. I think it's be an interesting read, flitting between the public and private but a hell of a lot of work to build the characters etc. It's been done loads hasn't it? I'll get my coat.
I've not read one published traditionally but there are several online. There is one on here somewhere about a little boy and a lady somewhere around the globe - it's funny. It is a modern epistolary so not a million miles away from a story like Clarissa.
Everything has been done before! Don't let it stop you from writing your story however you want to. Reading your post reminds me of Mika: an author who, a few years back (around 7-8 years ago, I believe), wrote her YA/romance novella, γζη©Ίγ (read as: koizora / english: sky of love) via a mobile phone site (I'm not sure if that's the right word for it? Literally, it's like a website that can only be accessed via a mobile phone rather than a computer). It went down well and has since been made into a successful television series and a film.
I would say that just about everything has been done or can be related to in other works, published or not. I personally believe that the characters make a story good and original rather than the plot or the format which it is written in.