Have friends or family members running in Sunday's marathon?

The beauty of modern technology means you can follow their progress with microchips that track each individual runner as they progress through the course. Sign up for alerts by phone here. A link will also be made available on the marathon Web site on race day with a database of unofficial results including clock time, gun time, splits, pace and placement.

Marathon officials are using a system called D-tag, which uses small electronic devices attached to runners' shoes to track finish times and progress through the race. Mats are placed along the course, and when runners cross the mats, their followers are alerted.