Read the full announcement here: https://raider.io/news/159-introducing-raiderio-live-tracking
Live Tracking allows you to have your Raids and Mythic+ runs instantly tracked via your WoW Combat Log. You'll get several immediate benefits with this feature:
Instant updates on the site. Right after you finish a boss or Mythic+ run the progress updates will appear right away on the site.
Improved reliability. The combat log will act as another source for data, so if a run or raid is ever not able to be tracked via Blizzard's API, it will be trackable via this feature.
Accurate group compositions. Raids and Mythic+ comps will now reflect the exact gear, and talents that each player was wearing at the time it was recorded. This even allows your raid kills to properly represent any cross-realm members.