The Scratch Pad tool is merely a front end to a folder of files. If you open a file in a text editor and change it, then switch over to the Scratch Pad and click on that file, you’ll see the changes in the writing area. If you add a file to this folder, you will see it pop up in the Scratch Pad list.
So that is your solution: write down your thoughts using whatever tool you prefer to do so with, and save that as a file to your designated scratch pad folder (which it sounds like you already have on Dropbox, meaning you can do this from any device that is attached to your account). Note that in the General preference pane there is a setting for scratch pad file format. You may find that plain-text is the best to use across all platforms. There aren’t many Android or iOS programs that can read and write RTF and RTFD files.
One other approach is the external folder sync feature (the File ▸ Sync ▸ with External Folder... menu command, which is documented in the user manual PDF, §13.2, starting on pg. 164). It is possible to set this up so that it works more like an “inbox”, and in fact that is precisely how I use the feature. Here is how I set things up:
- Create a folder called “Inbox” in the Binder (I usually give it the orange sync custom icon).
- Create a Collection called “Imported Notes”.
- In the
File ▸ Sync ▸ with External Folder...panel:- Disable “Sync all contents of the Draft folder”.
- Enable “Sync all other text documents in the project”.
- Enable “Sync only documents in collection:” → “Imported Notes”.
- Set “Import new non-Draft items into:” → “Inbox”.
- Now when I drop a file into that folder, the next time I load the project or run sync, it will be placed in the “Inbox” folder for me. Job done.
- When I no longer want the file two-way synced, I remove it from the “Imported Notes” collection. If a file is not in that list, then it will be removed from the folder in the next sync and no longer monitored internally.
The nice thing about that approach is that you can target specific projects with new files, whereas the Scratch Pad is of course a universal tool. I tend to work with around a dozen projects at a time. Putting all of my ideas for all of those projects into one central dumping ground would be untenable. I’d rather have a folder somewhere with a bunch of project-specific drop folders. This method requires more setup and maintenance, but I consider it worth it for the clarity with which I can say this idea goes here and that piece of research goes there.
P.S. I wouldn’t recommend Simplenote for anything at this point. We will be removing the integration soon-ish as the quality of their service has dipped below what we consider acceptable.