Every Listing and Profile on HomeExchange have an ID number.
You can check for the Listing ID in 3 ways:
1) On the listings's URL (address bar of the browser): https://www.homeexchange.en/homes/view/123456
2) On the listing public view: open the listing and scroll down. Under the "Additional information", you will see "Home ID":
3) You can check your own Listing ID in the My Home page, in the left hand side menu.
How to search for the ID?
If you know your exchange partner's Listing ID you can search for it in 2 ways:
1) Enter the Listing ID in the "Where are you going" box and from the drop down menu choose "see home xxxxx". As you click on it, the listing will open.
2) If you are already on another listing (yours or another members') you can simply change the number in the url on the browser's address bar.
For the Profile (user) ID, you can see it in the Profile's URL when you open the profile public page: