The signature is also supported by Adobe Reader Mobile 10.2

With the latest mobile version of Acrobat Reader, you can even easily sign documents.

Adobe has updated its PDF reader for Android and iOS. One of the most important new features of the new software is that we can sign the document using the touch screen of the phone. So far, this has required our signature to be scanned separately. Another novelty is that we can now easily take notes anywhere within the file. The easiest way to download the update is to visit Android Market or iTunes. The software is free for both platforms!

Source: engadget.com