I’d like the ability to use the Twitter style #Tag syntax within the cards.
This is a great idea! We will add it to the feature roadmap.
The same with autocomplete for emojis would be useful too with :smile: 
So I tried adding parent and children to my notes as @nikita.korobkin recommended me too.
My problem now is that it take long to navigate inside the hierarchy ( I have to double tap on the card title to see the children ) and the other thing is that I was trying to add inline link to each notecards but I noticed that each notecards have a limit of 1200 characters, which get used fast with inline link.
I really like using tags as keywords/buzzwords for each note, I wish I could insert them as inline tag within the notecard.
The advantage of using tag is that
1- I can find instantaneously what I’m looking for by using the tag filter (for example #Pictures cards from #Rubin’s book on #Pathology of #Liver)
2- when I’m writing a note just typing the first 3 or 4 letters bring up the tag that I’m looking for.
So as @rawkode requested, I wish inline tagging will be implemented soon .
Inline tagging is confirmed as an addition to our upcoming WYSIWYG editor. Thanks for posting your use cases here, it’s very helpful for us!
How can I use this today? I type “#” in a note and I dont see a way to auto complete tags or even create a tag
You have to first tap / or \ in order to bring the command prompt on card edit mode, then use any of the shortcuts such as # to add tags to the card 
An update on our end.
Creating new tags while editing a card inline is supported right now (using / or \ + #).
We will be further improving the tag creation flow in a future update, so you will be able to just type # to add a tag to a card → we hope this will resolve most peoples friction surrounding tags.
But this isn’t the same as “Inline tags” – where the tags are present within the middle of the body text in display mode and are clickable / filterable. This is something we’d like to do and is now possible with the introduction of our new editor, although we currently like the clarity of having the tags separately on the bottom right of a card and are easily viewable and clickable in one place.
More thoughts are welcome!
Inline tags would be nice and quite useful, but should have their own unique graphic appearance to set it apart from surrounding text, i.e., not just a hashtag, and definitely not an underscore. Maybe a kind of bubble with a color change, that should also show up if printed w/o color. I think the majority would prefer inline functionality since it follows a kind of stream of consciousness. Perhaps make it an option for tags to appear inline and/or at the current location. Notably, with tags inline, they would also show up in seamless view, adding more useful info to that view.
Personally, after having tried different apps and editors, I have come to prefer tags in a separate location, away from the main text. I can imagine an editor that responds to a # with a popup for selecting or adding a tag, as long as that tag doesn’t end up inside the text.
I actually like the tags as they are now. However, I could imagine a feature (on top of the current functionality) that an inline #tag would be also added down below the text, just like the non-inline tags. Deleting it the usual way would be prohibited as long as it occurs in the text.
I’m with Bard, and prefer having the tags in their current location, separate from the content of a notecard.
That approach to tags is opinionated and inflexible, but stops people making a mess of their tagging. For me, that’s one of Supernote’s big differentiators over the competition - making it easy to do the right (and good looking) thing, and harder to make a mess.