Google Search has removed over half of the indexed URLs from Twitter due to Twitter’s decision to display tweets only to signed-in and registered users. This has resulted in a 62% drop in index saturation of Twitter.com. The decrease in indexed URLs is evident from screenshots and a third-party tool, Semrush, also shows a drop in Twitter’s visibility in Google Search. However, Google still has access to new tweets through its deal with Twitter for the firehose. Old tweets are gradually dropping out of the core Google web search index, which means less visibility for Twitter and potentially impacts brands that rely on Twitter for visibility. It is uncertain if Twitter will reverse this decision or utilize supported markup for paywalled content to stay indexed by Google Search. Currently, Twitter appears to be facing several issues.

source: Twitter didn’t just block unregistered users, it blocked Google Search