Micropoetry is a collective term for a variety of different forms/styles of very short poems. As a poetic artform, it doesn’t really have any rules. Although it does consists of other forms of micro poetry with fixed rules such as haiku, tanka, senryu and gogyohka.
Although not set in stone, the general consensus for naming tiny poems on twitter seems to be the hashtag #micropoetry. But with the140 character limit, this hashtag can often be too long to append to certain poems. This is why many micropoets use shorter versions of this tag such as #mpy and #mp.
There are of course other often used microoetry hashtag variants such as #poetweet and #tweetpoem. I’ve tried to cover most of these in the extensive micropoetry hashtag guide.