A Twitter spokesperson told, “We have begun aggressive outreach to many users that have not signed into Twitter in more than six months to warn them that due to prolonged inactivity their accounts may be permanently removed.”  Twitter has not yet said exactly when it will make usernames available to existing users. According to the spokesman, the account removal process will take place over many months not just on a single day. So don’t expect to happen on December 12th with a big username rush. Maybe it’s a while.  This does not only affect people who have abandoned Twitter; it also has a huge impact on the deceased’s own accounts. If a bot or other secondary account has been set up, you should be safe as long as it remains active. It’s not uncommon to do this from time to time for huge online networks. Yahoo launched an effort to recycle accounts in 2013, though some people who picked inactive usernames wound up getting email addressed to the old account owner.  Keep in mind that to stick around, these accounts don’t really have to tweet something. They just need to log in and follow the instructions given by Twitter. So even if the username you want seems to be dormant for a long time based on activity, anyone who owns it can still easily hold on to the username. Usernames with less than five characters can’t be registered on Twitter anymore, so that’s something else to consider.