From 11:00PM PDT on Friday, July 1 until 5:00AM PDT on Saturday, July 2, the Shmoop engineering elves will be making tweaks and improvements to the site. That means Shmoop will be unavailable for use during that time. Thanks for your patience!
Annabeth calls them "terrible flirts" when Percy's sees them in the lake (7.13). They are part of the colorful community at Camp Half-Blood. A naiad is a kind of nymph that lives in bodies of fresh-water. They are beautiful lady-creatures.