The info beside the 'keywords' says up to 10 (and Zazzle say about 5) but I've noticed that other artists use a lot more than that. Is there really any point in adding every single word that you can think of that is vaguely relevant to one's card design?
 
I also noticed that some artists included a lot of keywords that had absolutely nothing to do with their design and I wonder how they got past the reviewers!  
 
Maybe that's why some cards come up in the wrong category too? For instance when I searched for Wedding Invitations,  one artist's cards that had nothing to do with weddings came up on each and every page!  

Thank you for replying, Peggy, and for the link - I wasn't at all sure which was the correct place to post this query!
 
I'm wondering why the Zazzle team would explicitly write in their newsletter that only the first 5 are likely to be useful for searches.  
 
Do you know whether the keywords/tags are for internal use when searching the website or for general googling? If it were for searching within the GCU/Zazzle websites that might explain the difference.

The text box for keywords allows you up to 250 characters, so any words after that will be cut off.   I've been told by web search optimization people that the first few keywords are the most searched by crawlers,  therefore the most important.  However once at GCU, all searched keywords will come up, so it is only courtesy to use any word that describes your card exactly, refrain or limit using vague keywords and never use clutter just to bring a card up in searches.  You will only annoy those searching for a specific card and worse, may even drive them away from shopping at GCU.  
 
It never hurts to go back to review and edit our cards in the card management window as hopefully we have learned some lessons along the way with our increased experience and going back and improving our old ones can only benefit everyone!  

It's one thing for Google to only care about 5 words, but people search for a lot more than that if they want to find something specific. I use enough keywords to describe everything I would search for, no more and no less.