Hey there,I can half see your thread but it wont work properly, do not know why. Here is your answer.
It is built in.Favourites
You can add Favourites to products using the tag which will allow someone who is logged in to add this. In their logged in area you can have page that outputs these favourites.
Older guide but basically the right steps - http://kb.worldsecuresystems.com/143/bc_1432.html