It seems my domain has been registered before, I find a few links to it and it's listed in "dropped domain lists" a few years ago. I dunno if this is a good or a bad thing. However, the domain was indexed a few days ago by google, and now it seems to be de-indexed. This has never happened to any of my other domains, is that a problem with domains that have been in google years back and since been deleted? Do I just have to wait to get indexed again, or should I do anything else?
Now the site is suddenly indexed again, the front page that is, is this normal? I've never had sites de-indexed like this before and I have more than 50 websites.
This can be just a temporary glitch, when the system can't find your cache for some reason. The the data push happens and it's suddenly there. It's possible that Google datacenters other than your own can still see it.
It's highly normal. You don't have to worry about the deindexing of the previously indexed pages as long as your new contents are being indexed. This is common with dropped domains back with new or different niche. I'd suggest you to give it some time and all the pages will be back.
Thanks for the replies, this is good to hear. Was getting a bit worried as the domain has been registered before.
since the the content of the domain is now fresh you don't have to worry.. google are still indexing the old backlinks of your domain and that's as long as you don't link back to them there's nothing to worry about..