Marketing your business on Instagram can be both good and very bad for photographers. You have to be very careful how you use this incredibly popular photo sharing site (and at the same time protect your images). Any image you put on it should have a very clear water mark with the message:
©Your Name / Date / All Rights Reserved.
I also put my phone number in there as well. ASMP has put up some very valuable info here on just what rights you give away but my feeling is if you have a clear watermark on your images you can use it for marketing effectively and still be protected.