iPhone: There are countless notes apps available for your iPhone, but Better Notes has a neat little gimmick that makes it worth a look. Instead of dealing with tags or folders for organization, it allows you to make Twitter-like hashtags that are easy to search through.
Better Notes works pretty much exactly as you’d expect. Create a new note, and if you want to link it to other notes, use a hashtag anywhere inside the note. From that hashtag, you can search for other notes, or you can use the built-in search function. It’s a tiny, simple thing, but it works really well because all your organization is in-line so you don’t have to remember to do anything. Better Notes also includes lists and image attachments, but the hashtag organization is really the main draw here.