The Samsung Galaxy S2 is one of the most popular smartphones on the planet at the moment. Although the device's features have been explained away on the Internet over the months, there are still a few features that may come across as something new. These are certain accidental or experimental discoveries by the users which you may or may not know about.
Here are the top six features.
Enabling Screenshots: This is one of the most surprising features of the device that was found by a user. If you hold down the Home and the Power buttons together, you can enable screenshots. You could give it a try.
The Notification Trick: A few users have found out that if you hold your finger down on the notification bar, after a few seconds it automatically turns into a brightness scroll. Here you just need to move your finger left or right on the notification bar to increase or decrease the brightness of your device. However, it is to be noted that this feature only works if you have enabled the auto-brightness.
Fast Calling: When you choose to make phone call, rather than going through the contacts, you can actually use the numeric keypad and type down the name of the person you want to contact. Just open the numeric keypad and start typing down the number of your friend and before you reach the fifth numeral in the number combination, the name of your friend will automatically crop up as an option. You can choose to either call or text him by tapping on his name.
Screen Lock: Did you know that if you press down the power and volume keys in the video player together, you can actually lock the screen? Give it a try.
Contextual Search: You can actually launch a contextual search by holding down the menu button. In the address bar just type in “about:debug” and hit the go button. Next, just press the menu contextual key and pull up the options and you can now go all the way to the bottom of the screen.
Moving Through Screens: If you hold down the little dots on the home screen and slide them across, you will be able to move through all the screens quickly. It can be a very convenient feature.
(Information from forum.xda-developers.com)