Twitter’s Location Features Will Be Completely Opt-In – It should launch soon, allowing you to tell where a Twitter user is located . . . if he/she so chooses.

Tweeting’ medics expose patients – Some doctors are breaching client confidentiality by posting about patients on Twitter and Facebook.

WARNING: Twitter Worm Spreading via Direct Messages – Don’t click on suspect links in direct messages.

Twitter to Become Tech’s Newest $1 Billion Company – It is raising $100 million in capital from seven investors, including T. Rowe Price.