Zpeech - chat at a given webpage by appending the URL, just like Gabbly and 3bubbles, although it is a little different as it is more of a permalink discussion board…webride also holds discussions pertaining to a webpage.
me.dium, inCircles, Chatsum (even leave notes), Itzle, Others Online, yakalike, Web2.0 Live Chat are similar, but don’t work on the fly by appending the URL. eg. if you want to chat whilst on the Google homepage, you and your friend need to go to, http://zpeech.com/google.com.
Try ChatCreator and Conversate for private chats on the fly, see Chat LinkBuilder for communal chats on the fly, or try your luck at BuddyStumbler and Tworl…also see IMVU for virtual chatting.
Shotcode and BeeTagg - create a barcode for a URL, when people scan this barcode with their camera mobile phone (need to firstly download the app on their phone), it contacts the servers and then sends you the URL to your phone…same idea as MyTago.
This could be big in the offline world, see a car you want to buy, scan the code, and you are sent information (as Bee Tagg mentions it could take you to their eBay page)…this is nothing new for retailers and librarians, scan a code and read the metadata.
Check out this clickable Tattoo.
Google Ajax News Bar - get a narrow ajax widget, looks really transparent and non-intrusive. Kind of reminds me of Gmail web clips. You can also get a verticle version that looks like your usual RSS to Java.
OmniPage - listen to PDF’s