An ant is a phenomenon that emerges from the interaction of genes as they react to the environment in the same way that an anthill is emergent from the collective behavior of the individual ants as they react to the environment.

Memes would be the basic building blocks of any organism that emerged from the manner in which replicated ideas collectively reacted to the environment. Arguably this describes human culture, though I think that's a long way from exhibiting independent intelligence (but maybe we'd be incapable of recognizing it).

Presumably something could emerge from the collective interaction of such meme-based organisms. Though like with ants, where the phenomena of an anthill can also be understood directly in terms of genes (all the ants are siblings), I suspect it could really just be reduced to the interplay of mutually reinforcing memes.

I wonder what the analog to delineating the internal and external environment is in the meme-based universe....

It's funny that you use those examples. In 'The Selfish Gene' where the term 'meme' originated, it's used to describe any 'things' that Darwinian forces act on. So things that persist and spread in the way that genes do, but aren't genes.

One of the examples used to illustrate the point was beavers' dams. So 'meme' always did exactly mean persistent phenomena like anthills and tuna shoals (although 'collective animals' would be a subcategory, it referred to more than just those). The word has recently been semantically narrowed into meaning 'a picture on the internet with some words on it'; sadly, in my opinion. The original meaning was much more interesting and useful as it ties in with Darwinism, or the theory of evolution applied more broadly and to things which aren't necessarily biological organisms.

Apparently Dawkins isn't bothered by it himself though and likes the current usage (or so I read somewhere).

I feel these constructs were always present (compare the behavior of a pack of wolves vs a lone wolf) but in our age they're large reinforced by the "pack" being orders of magnitude larger. See how lynch works in social media: someone gets accused of something, then an army of disgusted users carries on the attack, which is not only virtual today. Individual conversation in these circumstances is not possible: you're not talking to individuals, but to a Mob, an animal with it's own behavior and very limited reasoning abilities.

The communication with bots and computer systems that are designed to interact with humans and equipped with the so-called "AI" is of similar nature: it seems there is some exchange, but it's very shallow and limited by the abilities of the receiving end - you can never transmit anything new, anything that the system is unable to understand. Continued use of such systems might have hard to predict consequences.