The Massachusetts Convention Center Authority has signed agreements with Digitell Inc. and Attend.com to offer new services to planners using the Boston Convention & Exhibition Center and the John B. Hynes Veterans Memorial Convention Center. Digitell Inc., a provider of web-streaming services, will help planners to host more webcasts and live-streaming, as well as to capture content. Attend.com is local Boston startup that provides online registration and event management; its services are geared toward small to midsize events and include Internet, hardware and access to a wide array of registration functions. These include wireless nametag printing, mobile attendance-tracking, text-message alerts for VIP arrivals, and access to data and analytics following the event.