in IN, it can be used in context as a verb, noun, wish, blessing, greeting or reply.

verb/noun/wish/blessing/greeting are self explanatory.

reply as follows:
user1: hey DBS very fierce 2016 until now jan 2018!
user2: #huat

it can mean
1. people huat liao
2. yah very huat
3. you bought ah? huat liao lor
4. I have huatted :)

from: https://en.wiktionary.org/wiki/huat_ah
English
Etymology
From Min Nan 發啊 (hoat-ah), from 發 (hoat, “to produce, to pay out”) + 啊 (ah, “particle of exclamation”).

Pronunciation
(Singapore, Malaysia) IPA(key): /ˈhwʌt ɑː/
Interjection
huat ah

(Singapore, Malaysia) An expression used to wish oneself prosperity.
Verb
huat ah

(Singapore, Malaysia) to prosper

"I never knew what “Huat Ah” means. Was wondering the meaning when everyone wishes me that. Then, a friend told me that “Huat” means “Fa” or “Fatt“, which means prosperity." - http://tiffanietan.com/2011/02/huat-ah/