The board set up a shareholder rights plan, also known as a "poison pill" which as we clarified yesterday for the benefit of the company's overly dramatic, overly literal and overly snowflake employees, is not literal..

... and which is exercisable if a party - read Elon Musk - acquires 15% of the stock without prior approval, lasting for one year (if the pill had expired the day after the midterms it may have been a bit too obvious). The plan seeks to ensure that anyone taking control of Twitter through open market accumulation pays all shareholders an appropriate control premium, according to a statement Friday.

For a company that has struggled greatly with value creation - on Friday TWTR stock closed at $45.08, or 18 cents higher than where it closed on its first day as a public company, or $44.90 - a poison pill defense strategy allows existing shareholders the right to purchase additional shares at a discount, effectively diluting the ownership interest of the hostile party. Poison pills are common among companies under fire from activist investors or in hostile takeover situations.