For each conversation participant, DNS and WHOIS lookup are performed. IP is presented as Hostname, whereas WHOIS description is shown in a tooltip when specific conversation is hovered. Tooltip contains information about organization name, description, country, address, network range and more, depending on data availability. By clicking on the arrow keys in the bottom left corner of the tooltip you can switch to info for the other address in this conversation.
In screenshot above, you can see that the first address relates to organization located in Serbia, you can also see its address and network range.