Just happened minutes ago, so not much information yet.

I think it's likely that this article from Monday might have finally pushed it over the edge (since it's usually media attention that does it): You can’t offer to murder cops on Reddit unless you’re on r/TheDonald

The quarantine message says:

It is restricted due to significant issues with reporting and addressing violations of the Reddit Content Policy. Most recently the violations have included threats of violence against police and public officials.

As a visitor or member, you can help moderators maintain the community by reporting and downvoting rule-breaking content.

Here's the message the admins sent them:

Dear Mods,

We want to let you know that your community has been quarantined, as outlined in Reddit’s Content Policy.

The reason for the quarantine is that over the last few months we have observed repeated rule-breaking behavior in your community and an over-reliance on Reddit admins to manage users and remove posts that violate our content policy, including content that encourages or incites violence. Most recently, we have observed this behavior in the form of encouragement of violence towards police officers and public officials in Oregon. This is not only in violation of our site-wide policies, but also your own community rules (rule #9). You can find violating content that we removed in your mod logs.

As we have discussed in the past, and as detailed in our content policy and moderator guidelines, we expect you to enforce against rule-breaking content. You’ve made progress over the last year, but we continue to observe and take action on a disproportionate amount of rule-breaking behavior in this community. We recognize that you do remove posts that are reported, but we are troubled that violent content more often goes unreported, and worse, is upvoted.

User reports and downvotes are an essential way that Reddit functions to moderate content. Limiting or prohibiting them prevents you from moderating your community effectively. Because of this, we are disabling your custom styling in order to restore these essential functions.

As stated in our Moderator Guidelines, our goal is to keep the platform alive and vibrant, as well as to ensure your community can reach people interested in it. Accordingly, here are the specific terms of the quarantine and the next steps we are asking from you as a mod team to resolve this situation.

Quarantine terms:

Visitors to this community will see a warning that requires users to explicitly opt-in to viewing it. This messaging reminds users of the importance of reporting rule-breaking content.

Custom styling has been disabled to restore the report and downvote buttons.

We hope both these changes will help improve the signal around rule-breaking content and improve your ability to effectively address it.

Next steps:

You unambiguously communicate to your subscribers that violent content is unacceptable.

You communicate to your users that reporting is a core function of Reddit and is essential to maintaining the health and viability of the community.

Following that, we will continue to monitor your community, specifically looking at report rate and for patterns of rule-violating content.

Undertake any other actions you determine to reduce the amount of rule-violating content.

Following these changes, we will consider an appeal to lift the quarantine, in line with the process outlined here.

We hope that this process provides a viable way forward to restore the health of the community. However, if this situation continues to escalate, we will explore further actions, including the possible banning of your community.

Please confirm that you have received and understand this message.

Online/digital bookmarking and excerpting is something that really interests me because I think most if not all existing options for it fall very short of the functionality I wish existed, and that I think could exist.

One of the first online bookmarking services I used was Delicious, and for a few years it was irreplaceable for me. However it languished after it was bought by Yahoo and then resold, and since then I’ve observed its slow and steady decline from afar.

The purpose of this post is twofold:

1. I want to know the current state of online bookmarking for you. I’m curious to know if it’s as much of an unmet need in anyone else’s life as it seems to be in mine.
   • Were you once a bookmarker and gave up due to the seeming futility of it?
   • Have you never been interested in bookmarking and/or don’t see the point of it?
   • Are you an active bookmarker, and if so what tools or workflows do you use, and what kinds of content do you bookmark?
2. I thought I would share some of the research I did into Delicious’ various design iterations over the years via the Internet Archive. It’s a cool birds-eye survey of how the service’s ethos, goals and design changed over time. Beyond the value it provides as a case study, I think there are greater lessons and insights that can be gained from observing the rise and fall of what was once such a beloved online service.
   • del.icio.us | 16 September 2005
   • del.icio.us | 20 December 2005
   • del.icio.us | 11 October 2006
   • Delicious.com | 11 May 2011
   • Delicious.com | 27 November 2011
   • Delicious.com | 12 May 2012
   • Delicious.com | 30 August 2012
   • Delicious.com | 14 October 2013
   • The period between 2013 and 2016 seems to be one endless loading screen from the archive’s perspective
   • Delicious.com | 15 March 2016
   • At some point in 2016, they went back to their original domain name – del.icio.us | 14 May 2016

As a sidenote, I also found this explanation of Delicious' approach to tagging to be very interesting: del.icio.us/help/tags | 21 February 2006

I hadn't realized that Delicious was actually the first to introduce the concept of user-controlled tags for bookmarks:

When Delicious was first launched, it was the first use of the term "tag" in the modern sense, and it was the first explicit opportunity where website users were given the ability to add their own tags to their bookmarks so that they could more easily search for them at a later time. This major breakthrough was not much noticed as most thought the application at the time "cool" but obvious. – Source

Edit: I hope it's alright to edit a post this many hours after having submitted it. There were a few important updates that I really wanted to include here.