Some time ago I woke up with a story almost fully formed in my mind. This was inspired by a lady I had got to know very well online. She told a very interesting life story. Of course it is possible that as it was an online association, she may have been exaggerating or making things up. I don't let such things bother me. The scenario for the story was that she was a socially isolated person who had suddenly come to the attention of the intelligence services because of her unconventional relationship with a man who was suspected of committing a major crime. This man disappears from her life in the first cahpter. For the story to work she needed to have made contact with various people via a relationship type forum. At least one of these people would be based in Ireland and would arrange for her to be sneaked out of the country in a fishing boat. So for this story to work she would have to have made friends with a number of people who could not be linked to her directly by work or social contacts. While I did lay a lot of this one out and start writing out sections, I eventually abandoned it as I felt that the use of an online forum as a plot device felt just a bit too contrived. As I could think of no other way for her to have made friends with strangers, one of whom was in a different country, I have done no more with it. So, is using forums as plot devices corny? Should I resurrect it? It did have some beautifully visceral bits in it.
If you have to ask, it will be corny. Now go back and decide it won't be. Once you convince yourself that it works, you'll be that much closer to selling it to the reader.
All sorts of isolated people make large networks of friends they've never met and have relationships online these days. It happens a lot in online games. I've heard all sorts of weird stories about the sorts of people who get to know each other through online games. My wife and her friend oftem reminisce about all the odd things which happened when they once took a road trip to meet various people they knew through a game.