Twitter's new update - blocked people can still see your tweets, but it is harder

People can always see your public tweets, even if you've blocked them, by just logging out. Other workarounds include using a third party app to view your tweets, or using a secondary account (or even searching on Google). Twitter's released a new update in the last few days (people can now retweet themselves, which might prove interesting) and they've really tightened up the block function - but claims that 'blocked people can't see your tweets' are, and always will be, incorrect. The only way to stop someone (even one person) from seeing your tweets is to make your account private.

The conflict between people's own experiences of using Twitter, the information Twitter gives about the block (and other news reports) and what is actually possible when using the service is the reason for this update / post.

I used to think I had a reasonable handle on Twitter's block but how it is implemented (how it appears to the user) has become increasingly app- and platform-dependent so it's really not possible to say with much confidence what someone will see if they're blocked / if you've blocked them.

On official Twitter apps such as desktop / browser Twitter and Tweetdeck (owned by Twitter I believe) it seems that you can no longer see anything, no profiles, no tweets in search. If you've blocked someone you'll no longer see their tweets, even if retweeted - this is a new and positive step for most people. But...

Remember that third party apps (Echofon for iPhone, Twicca for Android etc) often behave very differently from official apps and can let people you've blocked see your tweets.

Every time Twitter updates block I see a lot of tweets from people commenting that others now can't see their tweets - but they can, always have been able to and always will be able to. Please let anyone that needs to know, know, thanks.

More detailed information for block function enthusiasts (can't just be me, surely!)
I've done a quick test with a couple of accounts and apps and, thanks to a handy alternative medicine quack who's blocked me and who helpfully provides a testing ground, I present my results below ;) Feel free to share your findings too in the comments... especially if they're different from mine.

Desktop / browser platforms 

Twitter for desktop / browser (ie twitter.com on Firefox)
Profile view: I can't see it if I try and visit, it says they've blocked me.
Search results: their tweets don't show up, and clicking on a reply no longer brings up their tweet in the conversation thread. This may be different on other browsers. A friend reported they could see conversation threads on Chrome (though only on multi-person tweets, not one-to-one conversations) however Twitter's had another update since the latest one and this may no longer be the case.
Embedded RTed links: Clicking on a referred link also fails to show me the tweet and returns "you are not authorised to see that status". In fact the referred tweets don't show up in search, only on profile of sender (tweet shows as 'this tweet is unavailable' and message is "sorry you are not authorized to see this status."

Dabr.co.uk - basic functionality Twitter app
Profile view: not visible
Search results: namesearch: their tweets show up, hashtag search: tweets show up
Embedded RTed links: Not seen specific examples but given their actual tweets are visible anyway...


iPhone apps 
Twitter for iPhone
Profile view: I cannot see the profile of an account that has blocked me, it says that I'm blocked.
Search results: I can't see any tweets they've sent in search results. Clicking on other people's tweets in response to the blocker's tweets also doesn't show their original tweet in conversation.
Embedded RTed links: These are where the blocker's tweet is retweeted as an embedded link. Clicking on these referred links shows "Error loading Tweets (401)" - previously it would have displayed the tweet and any conversation.

Echofon for iPhone
Profile view: I can't see any tweets (the message given is that they've made their account private, though that's not true) but I can see their followers / following list
Search results: their tweets show up in search results. Clicking on the tweet lets me reply to it or retweet it (comment RT only).
Embedded RTed links: Tweets show in search and appear as normal embedded tweets, rather than "this tweet is unavailable". However clicking on the tweet brings up a blank page.

Osfoora for iPhone
Janetter for iPhone
- both show tweets in search results

Android apps
Twitter for Android
I don't have an Android phone so can't test this myself but discussions on Twitter suggest that profiles are now properly blocked. I don't know about search results or conversation threads. Let me know, thanks.

Fenix for Android
I'm seeing reports on Twitter that this no longer shows tweets

Twicca for Android
Reports on Twitter suggest that tweets from blocked accounts are still visible. 


Conclusion
It's now a lot harder for someone to see your tweets if you've blocked them (or for you to see the tweets of someone who's blocked you). But it's not impossible and I often wonder if making it look as if it's harder just misleads people a bit. If your account is public, it's visible to everyone. 

Mute, block, private - the three Twitter levels of peace and quiet, but not much else

The three Twitter levels of shushing people are

1. Mute

Muting someone just stops their tweets from appearing in your timeline. You'll still receive any tweet they send you as an @mention or a direct message. Muting is useful for temporarily shushing people who are live-tweeting an event that you're not interested in while keeping all other lines of communication open. They won't know they're muted unless you tell them.

Can you see their tweets? Only the ones where they've tagged your name
Can they see your tweets? Yes (unless they've muted you)

2. Block 
Blocking someone means you don't see their tweets. None of their tweets will be shown to you including their broadcast tweets and any tweet that mentions you. They also can't follow you or interact with your tweets. It is possible that you'll still see something of them if someone else that you follow retweets one of their tweets. All of your tweets are still entirely visible to them however, blocking just means they can't communicate with you on Twitter.

Can you see their tweets? Yes but on official Twitter you may need to click a 'view tweets' button (see first picture below)
Can they see your tweets? Yes, but it may take more effort depending on what platform they use (in second picture I've taken the screenshot from Twitter desktop which doesn't show profile, but Echofon on iPhone does).

What it looks like when you block someone, on Twitter

What it looks like when someone blocks you
(on Twitter, tweets visible on other apps!)

They may know they're blocked if they look at your profile on official Twitter sites (desktop or Twitter for smartphone / tablets) but might not notice if they're using third party apps.

Blocking someone does not stop them from seeing your tweets however and even if they're shown a blank profile your tweets will still show up in searches. You can see screenshots of what a blocked account can still see (I tested it with a spare account) here.

If you have blocked someone know that they can see your tweets by searching for from:yourname.

Think of the Twitter block more as a "continue to site" hurdle rather than "you shall not pass" barrier. Most apps still show a blocker's tweets to a blockee (even when logged in) and blockees can always search for a blocker's tweets (even if they're logged in), or just log out.

Rather unfortunately an awful lot of people have taken the "you are blocked from following X and viewing X's tweets" to mean that "if you block someone on Twitter they can't see your tweets", which isn't true. 

2a. The missing impossible level
This is the one that everyone seems to want - the ability to really block one or more people from ever seeing your tweets while making all your tweets publicly available to everyone else - but of course it's impossible. Anyone, if blocked, can use another app, use another browser or log out, or search for the tweets of someone who's blocked them.

It is impossible to stop someone from seeing your tweets unless you make your tweets private and trust everyone that you've allowed to follow you.

3. Private
This hides your tweets from everyone except those accounts that you've allowed to follow you. Your tweets will not show up in search results and tweets you send to people who aren't following you won't be seen by them.

Can you see their tweets? Yes
Can they see your tweets? No (unless you give them permission to follow you). Remember that your followers can share your tweets by manually retweeting them (comment RT) or by taking a screenshot (or, worst case scenario, having their account phished or hacked).

If you want to see how much people can infer from your conversations, even though they can't see your tweets, run a search for to:yourname or just yourname. In fact I'd recommend this to anyone with a private account.