This is Twitter official app that lets you follow your interests, instant updates from your friends, and many more.
2- Skype
3- Google Voice
This app allows you to send free text messages to US phones and make international calls at very low rates. It actually accesses your Google Voice account right from your iPad.
4- Hey Tell
This is an awesome iOS app that lets users instantly talk with friends and family. It does not require any account.
5- Flipboard
6- Zite
This is a free personalized magazine for your iPad that automatically learns what you like and gets smarter every time you use it.
7- Diigo
This is an awesome social bookmarking app that lets you bookmark, annotate, add notes, images and make screenshots from any web page.
8- Google Search
This app lest you search the web faster and easier. It is the official Google app .
9- Genius Scan
Genius Scanenables you to quickly scan documents on the go and email the scans as JPEG or PDF.
10- iTalk Recorder
iTalk Recorder is a full-featured recording app with a streamlined and intuitive user interface. You can record and email your recordings directly from iTalk
11- Discover Apps
This is an interactive map of the App Store that makes it easy for you to discover new apps from your iPad
12- AppMiner
AppMiner lets you browse more of the top apps, gives you a better search, finds price drops, lets you customize your categories and much more.
13-Dropbox
This is a free service that lets you bring all your photos, docs, and videos anywhere. Any file you save to your Dropbox is accessible from all your computers, iPhone, iPad and Dropbox website.
14- Evernote
This is an easy-to-use, free app that helps you remember everything across all of the devices you use. It lets you save your ideas, take notes, capture photos, create to-do-lists, record voice reminders and many more.
15- iBook Author