Apparently, yes. From their website:
The Samaritans Radar Twitter plug-in was closed permanently in March 2015.
What was 'Samaritans Radar'?
Samaritans Radar was a free Twitter plug-in which used an algorithm to allow Twitter users to monitor each others’ posts. It was launched on 29 October 2014 and suspended on 7 November 2014. It was closed permanently on 10 March 2015.
Samaritans Radar used a list of keywords and phrases to identify tweets that indicated someone might be struggling to cope.
It then sent an email alert to users who had signed up to monitor that account, flagging the tweet or tweets in question and linking to guidance on the best way of reaching out and providing support.
The idea was to give Twitter users a second chance to see potentially worrying tweets from friends, in case they missed them when they were originally posted.
Samaritans Radar was designed to provide an online safety net, after a 2013 study found an association between rates of tweets per users determined to be at risk for suicide, and actual suicide rates.
Why was it suspended?
Samaritans Radar was suspended following negative feedback and advice, including serious concerns raised by people from the mental health community who use Twitter.
This feedback included concerns about privacy – as people being monitored were never notified or asked to consent – and concerns that the use of Samaritans Radar would people to censor their tweets, making Twitter a less safe space for people who were struggling, and seeking support and community.
The potential for Samaritans Radar to be used, not only by friends but by bullies, was also raised.
All data associated with Samaritans Radar was deleted.