Hmm, title ? Hadn't thought of that. It probably does add more constraints or conventions the user needs to respect, though, because there needs to be a way I can detect tags in a local note's content to convert them to SN tags while uploading, and the reverse while downloading. Tags as first line of content is easy : if first line starts with @, consider the rest as tags, else no tags... Tags in title need to be distinguished from the title text proper, if you require both (I know I would). So, title text first, and everything after the first @ is parsed as tags ? But then you need to be careful not to use @ in title text, etc.
Need to think about it a bit. Just don't hold your breath, unless you're a professional diver :-)