Contributions from accounts in the 'bot' user group are not displayed in recent changes or watchlists to users who have opted to 'hide bot edits'. Minor edits made by bot accounts to user talk pages do not trigger the "you have new messages" banner. Bot accounts can query the API in batches of 5,000 rather than 500.
For bot registration leave a request at Wikiversity:Candidates for Botship/En.
See Special:Listusers/bot for a list of users in this group.