Some of my favorite Web 2.0 Sites
I tried to keep this list manageable for a classroom teacher.  They are listed in no particular order other than requiring or not requiring an account.                                                                                                                                  Last update: 3/16/2015

Sites not requiring an account:

Sticky note web page
wallwisher (now called Padlet)
Collaborative typing

Collaborative whiteboard

Collaborative chat site

Virtual Tutoring / Classroom
Know Lounge (Added 5/6/17)

Collaborative drawing

Private Twitter-like site

Transfer big files
wetransfer (<2GB)
transferbigfiles (100MB for free)
transfer.pcloud (Up to 5GB files) (Added 3/20/16)
DropItToMe (Added 5/13/16)

Word cloud generating
Jason Davies (Added 12/28/15)
Wordclouds (Added 8/23/16)
Tagul (Added 8/24/16)

Fun presentation tool (Added 7/20/16)

Online polling with mobile devices
Tally (Added 11/30/15)

Text to speech

IVONA (250 character limit) (Added 3/20/16)
FromTextToSpeech (Added 3/20/16)

Speech to Text (Added 3/2/16)
TalkTyper (Added 3/20/16)

Online timer
Online timer/Random Picker/Plus
Name Picker Ninja (Added 10/2016)
Fantastic online simulations

Find copyright free items
URL Shorteners

File Conversion Sites

Online Printables
        Printable Calendars         
        Calendar Labs (Added 3/15)
        Print a Calendar (Added 3/15)
        Free printable posters
        Printable Paper (added 11/16/15)

Screen Sharing    
Rhyme Writing
Free Clip Art


Online Live Stats

Internet Live Stats (Added 9/30/15)

QR Code Stuff

Math Stuff
Eyeballing (Added 11/16/15)
SolveMe Puzzles (Added 8/27/16)

YouTube Viewing / Downloading
Watchkin (Added 3/22/15)
KeepVid (Added 9/28/15)
Or, use this neat trick: In the url, change "watch" to "watch_popup"  Example:

Online Audio Messages
RecordMP3Online  (Added 3/15)
Vocaroo (Added 3/15)
Online Voice Recorder (Added 12/29/15)

        Cueprompter (Added 11/30/15)

Noise Level Monitors 
Bouncy Balls  (Added 5/29/17)

Paper Writing Checker

Online Dictionary/Thesaurus

Free Animations

For the Music Lovers
Chrome Music Lab (Added 3/14/16)

Make Poster Size Prints
The Raster...(Added 11/16/15)

Bensound (Added 9/15)
hatnotes (Added 12/17/15)

Free Images
Photos For Class  (New, a favorite)
Copyright Friendly (Added 3/15)
Free Large Pictures (Added 10/15)
Disney Clip Art (Added 4/18/16)
compfight (Added 7/20/16)

Online Teleprompter
        EasyPrompter (added 12/29/15)

Gigapixel Pictures
        Gigapan (added 11/16/15)
        A gigapixel sample (added 3/5/16)

Learning / Review Games
Jeopardy App (Added 8/15)

Create Custom Maps
Create Custom Charts
PieColor (Added 1/5/16)
ChartGo (Added 1/5/16)
Online Chart Tool (Added 1/5/16)

Special keyboard characters

Online Typing Tools/Training
Fliptext (Added 11/16/15)

Writing Prompt

Free Stock Video Footage (Great for Green Screen) (Added 3/18/16)

Build Your Wild Self (Added 5/9/16)
WeaveSilk (Added 8/13/16)
        SmartyPins (Added 3/9/15)

Video Conferencing (Added 12/4/15)

Add Text To Pictures
PicFont (Added 8/21/16)
AddText (Added 8/21/16)

Cool mapping tool
geoGreeting! (Added 10/27/16)

Fill Your Screen with Word

Sites requiring an account:

Sticky note web page

Create your own poster/presentation
Presentation and document sharing
Collaborative Publishing

Event Scheduling
File syncing between computers
Use this link to sign up and I get extra storage

Make pdf's flipable
Here is a sample for you to see

Lots of fun things to do to your photos

Create slideshows (ask for education account)
Learning Management System

Online comic creation

Online, collaborative bookmaking

Online Testing/Quizzing

Screen Capture/Recording Tools

Texting Tools
Kikutext (This one allows for parent reply. Nice)

Free Images

Free Stock Video (Great for Green Screen) 

Collaborative Drawing Plus Much More

Online Video Editing