The simultaneous detection of gravitational waves (GWs) from the binary neutron star (BNS) coalescence, GW170817, and its electromagnetic (EM) counterpart marked the dawn of multi-messenger EMGW astronomy. The scientific impact of such joint observations is extremely rich. But, the hunt for such exotic transients is a needle in a haystack problem. The first step is the low-latency dissemination of data-products using gravitational-wave data that aid the follow-up. Here, I will talk about the low-latency data products during the LIGO/Virgo third observing run. I will also talk about the determination of detection efficiency for time-domain telescope and how it ties into the determination of transient rates.