Also, "protip" has been in use for what, two decades now? When does something stop being a meme and just become an idiom?
An idiom is a meme too
In the sense that it is a cultural artifact that is passed along from one individual to another, yes. In the sense that it is something annoying kids on the internet use that must be complained about, no, not necessarily.
I hate the abuse of the word "meme"...
Funnily enough, the abuse of the word "meme" is now a meme.
GamePro is, as far as I know, the originator, so sometime between 1989 and 1994 (first time I remember it). So, yeah, about two decades. :)