A meme is a _self-propagating_ unit of information. Like a gene.
Tangent: I would call a datum the basic unit of information. Not sure if there's an official word, given the prevalence of the Wikipedia article for unit of (digital) information in every relevant search.
This explains a lot and I am glad you answered this way, because it suggests that you may be open to the possibility that while, to you, memes serve no function, there are people out there, who can use it in a way that make the difference on whether it has an function inherently or not, largely irrelevant. Just like life.