If you are logged in there will be a link to view your own cards from the header, otherwise there are links on the members page for each member.
The cards page is split into several different sections. Each card location has its own section, and there are other information sections.
The initial page you see has the members level and card counts details.
From here you can select any of the "Mastered || Collecting || Keeping || Might Trade || Will Trade || Doubles || Undefined" options to view cards in those locations
Stamps, Coupons & Other page shows a users stamp cards, what coupons they have, what sprites they have collected, as well as cards that are pending in trade or in their shop
The Logs page has a log of recent card gains
There is a Settings option that affects the card pages except for mastered and collecting.
The setting: Show missing cards when viewing cards page (doesn't affect collecting)
If this is set to no, the page will only display the cards the user has, if it is set to yes then it will show blank cards for missing ones