With the tagline "watch your stuff," Sensr is a video monitoring startup that utilizes cheap webcams and a cloud-based service so users can monitor video footage of their homes and offices (or anything else) over the Web.
The service works best with a dedicated network camera that supports FTP, but your built-in camera or most any USB web camera can be outfitted to work. A motion detecting system can be set to notify you via a text message or email if anything happens ("Heading out of town for the weekend? Leave your camera pointed at the front door. If someone comes in, we'll text you.").
Images are stored and organized on the service (via Amazon S3) by time and day for later retrieval and users can also share their camera feed publicly on the site or on other social media sites. Future plans include implementing face detection technology and releasing a public API (currently in alpha).
More details about the service can be found at: https://sensr.net/