For any one of you feeling puzzled by this concept, I want to make a brief note concerning my personal use of it. I’m not posing as an originator here; numerous nerds and odd-balls have most likely used this term before in their own private and homely fashion.
I’ve been fundamentally influenced by two genres, pop and progressive rock. As things are, no category feels altogether comfy when trying to summarize my own approach. One ends up with syncs and divergences.
To begin with the musical and the former, progressive rock is full of surprises; deviations from conventional song-structure (as a rule rather than by accident), neck-twisting disharmonies, questions left unanswered or meant for the listener to contemplate. Pop, on the other hand, can provide that head-on-nail directness, the playful and eternally contagious melodies, the instant gut-feeling, whilst not always (maybe more by accident than as a rule) being too surprising structure-wise. Progressive pop, then, is to me an attempt, albeit not on an always conscious level (as things go with influences) to blend all of these elements to a varying degree depending on the dynamics of the song in question.
As for the lyrical, the subject matter of progressive rock is known to have quite some range. From the fantastic and imaginative, the fauns, angels, the distant castles and legends associated with popular mythological tales to anything that in common language might be called ‘intellectual’ lyrics. Pop, then, appears to be contrasting with its obvious tendency to be corny stuff (for you to define), yet with a charm and sometimes a ‘purpose’. Progressive pop then might borrow a bit of the two; lyrical ‘pretension’ doesn’t really have to collide with an affinity for the mundane and silly.
Grabbing toward both and in other directions not mentioned here, progressive rock seems to me to be that space in between. Maybe that space in between can show how the two genres are not diametrically opposed. And maybe that space is the creative core of progressive pop.