On some further thought, if we wanted to go even smaller steps, it may be even better to encourage people to use web browsers more, instead of getting tied into single-purpose apps.
A lot of web browsers offer methods to sync one's bookmarks and login info (for better or worse), and the portability of browser bookmarks compared to in-app favoriting/saving/bookmarking could be good ways to promote them.
Flipping it around, for those striking out into making their own sites, perhaps POSSE should be adjusted such that any syndication elsewhere is accompanied by reminders to sub to one's RSS feed for a more direct and portable way to follow for further posts.