I tend to keep a folder full of short text files and pictures for my notes. If the documents are each small, its pretty easy to scan through them using preview

I tend to keep a folder full of short text files and pictures for my notes. If the documents are each small, its pretty easy to scan through them using preview functionality in the file browser (Finder.app in my case). And the simple format means its easy to import/export/organize them via scripts or manually.