Currently residing on Harrison and Fourth above a Subway and next to a Whole Foods, Twitter headquarters is appropriately nestled in SoMa's tech-industry neighborhood. For now, anyway. "Media reports say that Twitter Inc. needs more space and is looking at the former Walmart.com campus in Brisbane, a city of 3,500," reports SF Weekly. "But losing Twitter would almost certainly slow San Francisco's momentum to become a high-tech hub. Just last year, the city was outpacing San Jose in courting venture capital dollars." And how. Here's hoping they stay put.