
I look at my google analytics every day and can tell when any of my domains take a hit.
Funny thing is WordWord.ca & WordWord.com both took a single direct hit 3 days ago.
This morning I get an email asking me how much for the .com or the .ca
When I saw the hit on both the .ca and the .com I knew immediately someone was looking for the domain and sure enough the inquiry came.
In my google analytics I search for the term ?forsale= and I can see every direct type in, referrer, where it comes from etc. So much more detail than what I get from a marketplace.
Another big hint is renewal time, whenever I consider dropping a domain I look at my analytics and if the domain takes traffic then I renew it.