since you say youve been in the kuro fandom even before BoC aired, could you tell me about how it was back then? :D ive always been interested in learning how internet culture used to be, how things eventually changed, how they improved/declined etc, more so when the current community is pretty much dead. was there an experience that marked you, what do you remember most fondly? was there an event that excited the fandom more than any other (like the release of a chapter or smth)? which blogs were the most popular? Its okay if you dont want to tho, i understand!
Super interesting question! I hope I can provide some equally interesting information in return.
Before the fandom had reached Tumblr, much of it centred around a forum, or at least much of what I knew. It wasn't originally a Kuroshitsuji forum but a sub-forum of a Bleach forum, actually. I think it was called Bleach Asylum? And I don't know exactly how it came to be but I think that Bleach forum had lots of sub forums for then-popular anime and manga but Kuroshitsuji gained so much popularity and the fandom happened to gather there, so that sub forum really took off and it ended up being an anchor point for the fandom. I used to always look for the most recent scanlations there, back before we were able to buy them legally.
I didn't actively participate in that forum but I lurked occasionally. It was full of wild discussions, one of which was the "two Ciel(s) theory"/"2CT" as it was called back then. It had a strong following on the website back then already. I sadly don't remember any of the other theories that were making rounds back then...
I didn't really participate in much fandom stuff back then, limited my art posts to deviantArt and my personal facebook... but eventually, I made a tumblr specifically to interact with the fandom.
As for blogs, I don't really like doing any name dropping, especially because it would go into some people who used to ship sebaciel and turned anti, and other stuff I'd rather not talk about. I do feel like back in the day, there were a couple of gigantic Kuroshitsuji blogs with massive followings that got a LOT of asks every day (to the point where it seemed like a full time job to keep up with them). Discussion around sebaciel was very different, there have always been people who disliked it but unfounded rumours like "did you know that Kuroshitsuji was supposed to be a yaoi" made rounds without people questioning it. That always annoyed me a little tbh haha.
There was one fan artist on deviantArt whose name I sadly don't remember but I think they were THE kuro artist in Western fandom back then because their style looked very similar to the anime style. I still see their art sometimes.
And fun fact on the side, I grew up in German fandom spaces and we had a big website called Animexx (I think it's still around) that was dedicated specifically to all things manga, anime, and related stuff. They had really convenient ways of browsing on-site fanart, fanfic, doujinshi, cosplay, and other fan creations, as well as forums and ways to host your own fan events. Until the early 2010s, I hung out there a lot so until then, my perspective is distorted by that German lens. I used to post my early Kuroshitsuji fanart there too.
If you have any more questions, feel free to ask! I feel like I could go on tangents for much longer but idk how interesting that would be.