Firstly, it took me a fair bit to realise that the book icon at the top was actually the menu button, and not just a logo linking to the home page. It's a neat idea (having the service logo act as the menu), but it's not at all clear to users, and should probably be replaced with a simple logo link and hamburger button instead.
Secondly, forcing users to log in to view any content is not a good design pattern, and has been seen as a bad idea in the community management world for decades. Scrap it, let people view at least some content as a guest.
Stylistically it isn't too great either. It works on a functional level, but all in all, it just feels very... dated. Like, the site was made in 1995 type dated. That's probably because the colour scheme feels drab and uninteresting, the fonts all staid and the general structure of the pages is all so academic and formal looking. It reminded me of one of those 'guestbook' features Microsoft FrontPage used to have, and not in a good way.
So again, change that up a bit, since the vast majority of the population have design tastes that are a bit more up to date than Lyra's here.
Not sure the tour is a good idea either. Facebook, Twitter and others like them don't need one, and the way it's implemented here feels a bit overbearing more than anything else.
Do like how profiles let you add new fields yourself though, that seems quite useful (especially in an era where new social networks and their respective profile links keep popping up every day).
As for conversations, those just feel a bit awkward at the moment. I mean, are there any groups here? Any tags? Hashtags? Any way of categorising content at all? Cause at the moment, it seems like it's just a list of conversations about whatever random topic that you're somehow supposed to find and wander into. Not sure how user friendly that is myself.
Overall though, it's a mixed bag. There are some neat ideas here, and I admire you for creating your own social media site, but the design aesthetics and general setup just seem so dated it isn't a viable competitor to the likes of Facebook and Twitter for me.
Sorry.