Couple things regarding the text box.
Emoticons
If you start to type the code for an emoticon, then the options that match what you have typed should appear.
For example lets take the thumbs up emoticon ( ) . For that the code is either of the following two options
:aok:
:Aok:
If you start to type that code you should see the following pop up (may take a second or two)
The more letters in a Emoticons Code name you type, the more fine-tuned the list will become.
*note that typing native forum emoticon code while using a mobile browser, such as that on a cell phone, will bring up the forum emoticons corresponding to that code (in addition to those which may be native to the mobile device itself)
Member Mentions
They have finally added a "Mention" ability.
By typing @ followed by a members name you can Mention a Member in your post. Please note that by using this feature the forum will automatically sent the mentioned member a notification (per their notification preferences)
As an example I'll mention myself..
Here is the code you would use to "Mention" me in a post.
@RedPath88
Starting to type that will pull up a list of members similar to this.
The more letters in a members name you type, the more fine-tuned the list will become.
This will result in the following in your post
@RedPath88