We generally don’t really like the idea of portfolios because every project is different and what makes each client happy is different but sometimes prospective client’s want them.
How do you present your portfolio’s?
Leaving it vague as I know there are co-ops doing a lot of different things. For us, we’re mostly being asked for portfolios for front end web development.
As someone who has reviewed vendors before for a website development project;
I just wanted to see links to the websites that were still using the design that the vendor made. I want to go to the site and poke around and see how it does/doesn’t work. I also like to see adoption statistics.
I also wanted to call the people who received the designed site to ask them questions, though it’s probably a bad idea to publish their numbers on the portfolio 
Just my opinion.