Might be helping in the derailment of the topic, but in my opinion, I'd rather take likes than a bookmark any day.
A like means that someone might've scanned my chapter, or it's just the story owner (probably) appreciating that I contributed to their story. This is also why I give likes to those that write in my stories, as a way to show appreciation and motivate them to write further.
As for bookmarks, well, they're no help. As I see it, someone thinks your story's interesting, or maybe a chapter, and possibly never show up again while an upvote is printed at the bottom of a chapter - and in my head, it's much more validating than a notification saying "oh hey, somebody noticed your story and might read it."
Comments, however, are much more valuable (to me at least) as it mean that someone took some time of their day, read a story, and comment on it. Granted, they could be a variety of things such as constructive criticism, chapter ideas, simple approval or praise, or it could be someone I'm having a conversation with has replied, however rare that is. I see this a lot in Marcie and Gina, and it's one of those rare places that people - other than the forums - really interact with one another.
But of course, that's just my personal opinion.