I don't even think Mastodon is a replacement for twitter. It's too community oriented, our reach is barely outside our niche let alone the overall sphere of which it exists in. I don't think its a place people can come and expect to sell a product to a mass audience or go 'viral'. It's this fragmented assortment of loosely connected communities sharing content between one another. People coming to Mastodon expecting a twitter experience won't get that at all IMO.