We need to load these web apps manually from manage extensions settings. To load web apps click on developer mode (+) mark and then click the load unpacked extension button. A browser window will open where you have to locate the web apps folder. After locating the web app folder click OK and it's done. Now you can find the web app icon on new tab home page.
Here are few of web apps created by me for facebook, twitter and meebo. You can download these files from the link below. Open the zip file and copy web app folders to resources directory and load it into chrome. Follow the procedure I mentioned above.
Web Apps Download Link