Twitter has introduced a new blocking policy that is materially different from the one that they’ve had in the past. Blocked users can now see your tweets while logged in and continue to follow you on the service, allowing potential harassers or abusers to continue to track your updates on the network, even though you’ve explicitly blocked them.

This greatly reduces the effectiveness of some aspects of the block functionality on Twitter and opens the door for those who have been harassed or stalked on social networks to have their updates monitored more easily. Blocked users can now retweet your tweets, fave them and RT them while logged into their account.

TechCrunch spoke to Twitter about the changes, and the company says that the change, which does not notify or alert the person you’ve blocked in any way, was done to prevent a scenario of retaliation. The company said that they had seen situations where users, once they discovered that they had been blocked — because they could no longer view tweets or interact with tweets — would find other ways to attack or harass the blocker or even be spurred to greater abuse.

This new method means that the only way to prevent someone from following you or interacting with your tweets is to make your account completely private. This will prevent anyone you block from seeing your tweets.

While we doubt Twitter had anything but good intentions here, the consideration that a blocker might be antagonizing someone they’ve blocked will likely not sit well with victims of harassment.

It’s worth noting that you could previously view the public tweets of users that had blocked you while logged out of the service — and by visiting a profile page. But now they can do it while logged in and interact with them. If you’ve blocked them, you will not see these interactions, but others will, and those you have blocked will still be able to fave tweets, for instance, and see those in a list of tweets that they’ve faved.

This new blocking method is more of a mute filter that prevents you from seeing any tweets or interactions from a blocked follower. But those interactions still happen. In some ways, this new method is actually a more accurate picture of what happens with a Twitter account when you block someone. They could always see your tweets and manually RT them to their followers by copying and pasting text. Now, however, they can do so within the constructs of Twitter — you just cannot see them. Though their followers and anyone searching for your name can.

Twitter notes that those tweets may also show up in your searches.

Here is the current blocking policy:

If you block another user, you will no longer see:

• The user in your follower list
• Any updates from that user in your Home timeline, including any of their Tweets that were retweeted by accounts you follow
• Their @replies or mentions in your Connect tab
• Any interactions with that user’s Tweets or account (i.e., favorites, follows or Retweets) in your Interactions or Activity tabs

Twitter also notes the following:

If your account is public, blocking a user does not prevent that user from following you, interacting with your Tweets, or receiving your updates in their timeline. If your Tweets are protected, blocking the user will cause them to unfollow you.

And here’s the previous policy:

Blocked users cannot:

• Add your Twitter account to their lists.
• Have their @replies or mentions show in your mentions tab (although these Tweets may still appear in search).
• Follow you.
• See your profile picture on their profile page or in their timeline.

The changes to Twitter’s policy may indeed prevent some immediate knowledge that a user has been blocked, though they didn’t get a notification before and still won’t get one now. It could cause a lag between the time that they get blocked and when they realize it — but the scenario by which this could prevent retaliation once discovered gets blurrier.

Many Twitter users who have been abused and who undergo continuous harassment on Twitter — especially women — will likely not be pleased that their tweets can now be easily favorited and re-tweeted within the confines of Twitter’s platform. Yes, their tweets were never truly private because Twitter is a public service — but a policy that makes it easier to interact with tweets and add commentary to them (even if it’s not visible to you, personally) seems like it will cause many to cry foul.