This one's been eagerly anticipated. It's nowhere near perfect, but it's definitely a step in the right direction and takes far fewer steps than recording a Google Hangout just to capture a simple screencast. Below is an embedded video made using the free Google Extension "Screencastify".
During a Google Sites project earlier today, a student asked whether it was possible to use just a portion of a YouTube video. I recalled being able to do this through other web applications, but only where you would be able to start at a certain point (http://youtubetime.com/) or by manually modifying the link (http://google.about.com/od/googleblogging/f/Time_YouTube.htm). A quick Google search revealed a tool that's actually been out for awhile (where have I been?), but I'm happy to have found it today.
TubeChop is extremely easy to use. Simply paste the URL or even search directly from the website. Use the sliders to designate start/stop points for the video, and chop it. You'll get a dedicated URL for the chopped video, as well as a link and even an embed code. This was a perfect match for the website design projects, as the students now have a way of showing just a specific piece of some potentially long videos.
Recently, I attended a conference presentation on Subtext, which looked awesome on the iPad, but sadly, the web version is still in its infancy. I just gave it another go, and couldn't find an easy way to upload and start inking on a PDF. I had demo'ed PDFescape during a recent presentation on Chromebooks and Accessibility, and the web application gets the job done, but it does so with an abundance of ads, as well as some clunky behaviors.
So, in preparation for a meeting with a teacher who is interested in having her students annotate on the Chromebooks, I stumbled upon Crocodoc and I must say that I am impressed. Right from the initial first use, the interface for Crocodoc is very clean, minimalist, and easy on the eyes. The feature set is extensive for a web app. You can write comments on the margins, add pointers, box or highlight text. Free hand drawings, highlighting and text boxes are also one click away. So far, all of this has taken place without needing a login. You can even collaborate with other users by sharing a link or via an email address, and the notes appear in near real time. At the end, you can download the either or both the original and marked up text. Signing in with an account gets you some additional features such as upload history, the ability to delete files and management of folders and documents from one location.
I'll post an update once the teacher goes live with the assignment and tests on the Chromebooks. However, for now, I've found my go-to app for PDF annotations.