I am not very smart and exist far away from the California startup culture (I live in Atlanta, home to a whopping one app startup... Beloved MailChimp) but these are my predictions.
  1. It won't get TOO big.
    As predicted by my earlier list... I think that in the near future at least, The List App will avoid the sudden over saturation that Pinterest, Instagram, Tumblr experienced (each in their own way). It certainly won't fall into the commercialism trap that Pinterest, Instagram, and so many others did. It will remain a diverse community not based on age or gender (looking at you, Snapchat and Pinterest) but on creativity and progressive discussion (little "p"!!!).
  2. Twitter will be the first to be interested in purchase.
    The List App takes all the principles of Twitter: text first, pictures second, strong limitations with word count, etc. It would be easy for them to develop a new post type that's a list. Would fall well into their business model of expanding by offering new separate products (Periscope, Vine) which offer new but highly limited ways of posting (All types of Twitter posts have a time limitation, be it character count, duration, or the ephemeral limitation of Periscope).
  3. Think about it...
    Twitter for me today is just a giant feed of content producers linking to their crappy Listicle. Lists in Twitter would integrate the list natively making it a win win. Twitter keeps people on the site and within the realm of their advertising and the content becomes more engaging. YouTube style revenue sharing with ads would be inevitable.
  4. If List App doesn't sell... Twitter will copy.
    It isn't exactly the most patentable of ideas. It's not a stretch to stitch tweets together into lists. This is my most likely scenario. I am 78% confident.
  5. If not Twitter, it will be a content provider/new media conglomerate.
    A lá Buzz Feed. Makes sense and could easily be recycled into the app/community for user generated content.
    Trust me, I don't want them to happen any more than you do. Just some logical outcomes I see happening without having any inside knowledge.