10 things in tech you need to know today

Good morning! Here's the tech news you need to know this Tuesday.

1. Amazon has launched a grocery store with no cashiers or check-out lines. But it is missing one of the most important parts of its business - Prime benefits.

2. AOL's Tim Armstrong is "cautiously optimistic" that the Yahoo deal will still go through. The deal has taken a long time to close after Yahoo admitted a catastrophic hack affected 500 million user accounts.

3. Apple CEO Tim Cook claims Apple Watch sales set a new record in the first week of holiday shopping, Reuters reports. The claim comes after reports that its Q3 sales plummeted year-on-year.

4. Facebook, Google, Twitter and Microsoft are teaming up to tackle extremist content, The Guardian reports. They are going to create "digital fingerprints" that can track content that promotes terrorism.

5. Mark Zuckerberg reviewed the coolest stuff Facebook's engineers are working on. The social network held a hackathon, and projects included VR controllers that change temperature and offline messaging.

6. Two months after the Galaxy Note 7 debacle, this is the best theory explaining why its batteries exploded. An engineering consulting company thinks the phone's battery was too big.

7. Snapchat is hiring experts to "sculpt" 3D digital characters for new "visual stories." It is hiring people with experience in performance capture and game design.

8. A lawsuit alleging Mark Pincus and Zynga insiders dumped shares before the stock tanked is alive again. A group sold hundreds of millions in stock weeks before it announced earnings that sent its value tumbling.

9. Autonomy founder Mike Lynch says his $1 billion (£780 million) fund has backed close to 10 companies so far. He was speaking at the TechCrunch Disrupt conference in London.

10. Microsoft has launched a new chat bot on messaging app Kik, The Verge reports. Its last bot, Tay, turned into a genocidal racist after learning from its users.