Bluejacking is defined as where anonymous Bluetooth mesages are sent which is usually from one phone to another. The recipient needs to have their Bluetooth turned on and their phone set to be 'discoverable’, basicially this means they will be able to be found by other Bluetooth devices in range.
Bluejacking is usually harmless, but because bluejacked people generally don't know what has happened, they may think that their phone is either not working properly or it has been hacked into. In most cases, a bluejacker will only send a text message, but with the wealth of modern phones on the market, it's possible to send images or sounds.
Bluesnarfing is also known as the unauthorized access of information from a wireless device through a bluetooth connection that usually occurs between a range of modern technology including phones, desktops, laptops and PDAs.
This allows the hacker to obtain access to a calendar, contact list, emails and text messages, and on some phones users can copy pictures and private videos. Bluesnarfing unfortunately is much more serious than bluejacking, but both tend to exploit others' Bluetooth connections without their knowledge.
Any device which has its Bluetooth connection turned on and set to 'discoverable' may be susceptible so it is important you do not give out your details to unknown people or anyone who you do not trust as it may be susceptible to Bluejacking, and possibly to Bluesnarfing.