the like want own buttons only appear in certain categories.
I don't know why.
I understand that they are related to facebook.
If you return to the category and again click one of the 'like or want or own' buttons, then I think you can opt to 'view your ebay favorites'.
that opens a page with your likes, wants, owns.
If you type the string
ebay like want own
into google, the first item returned is this
http://www.ebay.com/soc/favorites
which lists your favorites (I think)
Also on that google page are enough references to find out more about likewantown.
The likewantown buttons and the list(s) don't seem to be integrated into the myebay pages (?)
The watchlist on the other hand is highly functional anduseful for buying on ebay.
http://pages.ebay.com/help/buy/watching-items.html
Click 'add to watchlist' or 'watch this item' and then see the list of links to your watched listing on myeBay / lists / watch list