Something that is always in our hands nowdays, the mobile phone is a great way to engage with donors and give details of a particular campaign. It's easy to do, gets around the issue of compatibility of websites on mobiles and is something that is more likely to be seen, particularly as many pop up with a small section of the text on display.  This is unlike emails which may go to spam, promotions or simply be unopened). 

I have had a charity recently compliment their email campaign with SMS and it has really ingrained their organisation and their cause in my mind. Could be good for certain seasons as well e.g. Ramadan, Christmas, etc.