Oh, you mean you didn't see the last sub-clause of the last paragraph of the third section of the announcement page linked to from the page above? /s

"a new link-aggregator-style community site that's starting its invite-only alpha today"

Seriously, site creators and submitters, you need to do a better job of explaining what you're talking about!

It's in large bold text at the very top of the post:

If this is the first that you've heard of Tildes, you should start by reading the announcement blog post (https://blog.tildes.net/announcing-tildes) for general information about the project and its goals.

Tildes.net says it's invite-only and leads to a blog post about the announcement of Tildes, but you have to parse the language to understand what it is. I honestly can't stand sites that assume you know what they are all about. Just a couple of sentences describing what it is and why you should care on the main page would be nice.

I read the linked blog post about what it is, and I still don't know what it is. I guess it isn't for me.

Had the same problem. Got wisps of information about it being like reddit, like HN, like etc

Most useful information I've seen so far is the previous discussion here on HN [1]

A quick summary: Ex-Reddit employee creates own version of Reddit. Upvotes intact but downvotes replaced with what looks similar to Slashdot's moderation (tag it Joke, Noise, Offtopic, Troll, Flame) in more of a downvote with a reason

Screenshots: https://imgur.com/a/qit6zPk

[1] Previous discussion https://news.ycombinator.com/item?id=17103093