Sort:  

Was my first guess too, but try to use it in a sentence.
"Did you upsteem this" sounds much better than
"Did you steemup / steemuped this"

Just steemup'd your suggestion ;)

Haha. .Thanks a lot @gigafart .. you know what GyaniBilli means? Wise Cat :)

Steemup doesn't sound so bad, but upsteem is what I'd prefer personally.

Upsteem is closer to the idea. I vouch for that. It will be upsteem and resteem. So it be simple to understand.