Enable Keyboard shortcuts in Gmail
1. Goto Gmail.com & login into your account.
2. Click Settings link at top right.
3. Under ‘General’ tab, click to select ‘keyboard shortcuts ON’ option.
4. Then click ‘save changes’ button & you are all set to use shortcuts.
Keyboard shortcut hotkeys for Google Buzz
gb to open Google Buzz in Gmail inbox [gb stands for Google Buzz. Easy to remember, isn’t it?]
n to goto newer or next conversation [n stands for new]
p to goto previors or older conversation [p stands for previous]
j to scroll through displayed conversations or items. [j for jump]
o to open or expand any conversation [o stands for open]
r to add comment to any conversation [r stands for response]
m to mute a conversation [it removes specific conversation from listing]
Shift + l to like a conversation [l stands for like, same as in Google Reader]
Spacebar for page down action.
Shift + Spacebar for page up action.