This is a lengthy discussion, and a very good one!
Luckily, Game Art Producer extraordinaire and very good friend Jon Jones (not the UFC fighter, BTW) has done an extremely insightful blog post about what to do and what not to do when putting your stuff online.
CLICK HERE FOR AWESOME PORTFOLIO ADVICE.
The things he mentions there are so relevant I apply them to my own portfolio.
Also, as a bonus, if you are aware of GDC and are subscribed to their "vault" series of videos, they do extremely popular “portfolio review” panels that are filled with additional, detailed tidbits of what recruiters are looking for in the industry.
Now go forth and prosper!
Cesar’s droppin’ some awesome advice today.