I'm sure this happens a lot to many of us. Even though I'm super passionate about what I'm doing right now, as it's our second nature as entrepreneurs, shiny new ideas pop up in the brain too often. I tend to write them down in my "write once and never see it for 6 months" list and forget about it.
Kind of struggling to figure out how to pitch my site wacht.tv, usually I just say its Reddit meets MTV. Maybe I'm overthinking it but I rarely see X meets Y as a tagline.