It can be hit or miss. I have found at times that it's more management than it's worth. Most of the time I have instead taken the same budget and hired a part time virtual assistant for the same tasks and gotten better results.
Now, there's certainly something to be said for building your community and hiring local interns from local colleges in order to give back. I do think that's a real and important motive. If you are set on an intern you might reach out to marketing professors at local colleges and see if you can back channel and isolate great students from their classes, though at this point in the season you are going to be late. Most internships for top students are going to be solidified early in the Spring.
This goes without saying for any job, but you want to make sure you carefully write down and explain expectations and remember this will be someone who has not worked before (much) so things you take for granted with an experienced professional might not be second nature to them. That said, social media and online is going to be a good area for this generation of young workers.
I've had good and bad experiences.
I have had pretty consistent and positive results hiring interns from my local university. I would suggest they be enrolled in graduate level programs, though.
Has been pretty hit or miss at the undergrad level.
I work at Long Island University here in NY. Of the stores I manage on campus, all of the employees are students,which is most likely what your interns will be :).
When working with students, or honestly anyone I've worked with including myself, it's important to assign them work that they actually have an interest in doing; not just going to collect a paycheck. For your particular job you're looking to fill, social media marketing, you'll probably want to reach out to the career services offices within local colleges and universities, and explain that you're looking for students with a strong interest, or major, in marketing. This will narrow your selection of possible interns, but save you the hassle of having someone on staff that is only their to collect a check. Colleges love having partnerships with companies and offering their students resources like jobs and internships, so you shouldn't have a problem making that connection.
When hiring students here, I always let them know that "...if you're here just for the money, it's not worth it. You can find a better paying part-time job elsewhere. If you want to be part of building of something, then you're exactly in the right place." Those are my words of inspiration that SHOCK the students I interview, but they get the point and everyone's happy in the end. You'll end up with people that want to do the work, and love learning beyond the classroom along the way.
I hope this was helpful. I'd love to hop on a call to help you with any further questions on getting those contacts at schools nearby, or any other questions in general. Good luck!
Interns are a great way of getting work done at a relatively low price - it can really help when you are having trouble covering wages. However it really depends on the Intern - otherwise you giving responsilbility to someone with practically no experience. Yes the younger generation has an advantage on social media, but they dont really understand social media, strategies, campagins or engagement. Hiring an experienced social marketer will save you more time and money, as the saying goes - You get what you pay for, and interns are FREE - there is a reason they are free - because you are providing them the training they need.