About Tildes, it seems to be more of a clone of Digg in the old days.
It may resemble digg 1.0, but it's intended as a spiritual successor to pre-diggpocalypse reddit. It's a project by the guy who originally built Automod and is very much like Reddit was just prior to the launch of the subreddit system - two years before digg 4.0 launched and the refugees started arriving.
Intended to be more of a wide-open commons than a platform for subdivided or niche communities.
Tildes has very limited adoption during the reddit protests because it's on an invite system and doesn't want a huge influx of new people all at once, for all that it is accepting and even seeking growth over time.