I think this website would appeal to kids to foster comprehension strategies--lots of visuals and good clear voice as students (grades 3-8--probably best) self select what they want to do (e.g., visualization).
Symbaloo allows you to set your own desktop to the websites you use most often. I see lots of potential for organizing your classroom computer for display purposes, particularly with young children.
Thinkfinity (which is supported by Verizon only) provides educational resources, lesson plans and more. There are professional development opportunities within the website (e.g., workng with refugee families), though there is no information on the background of the presenters nor whether these reflect professional literature. Nevertheless, looks interestng.
Audio recorder--easy to use--can send digital audio over email, add to website. Free version allows up to 1 minutes of recording, which is fine for most purposes.
Audioboo allows you to record podcasts and upload to web; designed for mobile phone, but can be done from PC too. Can embed on website our automatically upload to Twitter or Facebook. Lots of potential.