Player Cards

How much risk is there in signing up for and using player's cards at the various casinos? Does it give the casino's too much information about you? On the other hand, is it too conspicuous if you DON'T get one?

Also, can someone tell me how to register my name here - does it require signing up for CBJN?

Finally, are there ways (for the average person) of tracing posts on this website to the originating computer? How much do you think casino's review these posts trying to make connections with actual players?

Any insights appreciated.