If you want people to use #hashtags, show the tags (trending tags, displayed in picture apps, ...) + allow following

If you want people to post #threads, show them as actual threads + optimize thread creation + allow bookmarking

If you want people to #zap more, show the zaps nostr:nevent1qvzqqqqqqypzp22rfmsktmgpk2rtan7zwu00zuzax5maq5dnsu5g3xxvqr2u3pd7qy88wumn8ghj7mn0wvhxcmmv9uq3zamnwvaz7tmwdaehgu3wwa5kuef0qqspu07wx0kjna82yp4f3tzkpj4vgyd7jmg8jl96qpljx5uuh24hnps2g4src