You can now see your notification list while logged in at mocbuilder.com/notifications. Currently, the actions shown are: when another user likes one of your MOCs, comments on one of your MOCs, or follows you. Because this data is already stored with timestamps, your notifications list should already have entries from the last few weeks and months.
This was a feature that didn't have super high priority in my mind at first. But it was requested by a few users with the very good point that it was difficult to know if someone liked or commented on your MOCs. Thank you all for your continued feedback!
There's not currently a way to mark notifications as "read" (past tense) so there's no concept of "new" notifications, but I'll work on this soon as well.
I'm also considering allowing users to opt-in to receive emails when another user comments on their MOCs. I think this would help encourage more conversation. Let me know what you think!