One the forum once you started messaging with someone you can add another person to the conversation. Ond the main site you can't. I have discussions with other writers on my story and just realized that I would have to create a whole new conversation the next time I get a new writer and that this writer wouldn't have access to the ton of stuff already discussed. So it would be great to have the possibility to add a new person in a conversation in messages on the website. On a related note, in addition to the display older messages button there should be a display all messages one. Getting back hundreds of messages tent by ten is a real pain.
Is there a way to search within messages similar to searching for authors and stories? I like your idea. I haven't had a chance to think of where I could use it, however I'm sure I will need it down the road someday
No but if you have all messages displayed and know what to look for you can always use ctrl F on a pc, or sur search on the page in the browser options on mobile.