Right Now I run a web design business and I also do Affiliate Marketing. Explaining affiliate marketing is always a hassle since I end up explaining the process when I'm asked what it is I do so sometimes I just end up leaving it out.
How do you quickly explain what you do?
I would say, "I put the right people in front of the right offers". Or be a badass and call yourself a bounty hunter, of the internet variety.
After some split testing telling people what i do, i have 2 versions.
1. For people who are a bit techie
"I contact companies and sell there products for them through my own website/advertising and make a commission"
2. For the non-technie crowd and the shawties love this one.
"I flip websites". Then i go into how i buy a website, expand the userbase and value and then resell it.
I find customers for other businesses.
AM can be explained effectively through non-verbal communication as well:

Ahaha. Nice one mcr!
An easy one I use (well, AM is my second "job" but it's bringing in good loot): Performance Marketing.
I usually say like: "I'm delivering more customers to different companies".
Middle man in getting customers to larger business'
If all else fails, Drugs.
i'm an online marketer.... you know those dating and diet ads you see when you go to your favorite website..... that's me
everyone knows what you're talking about when you mention the ads.
"I run a direct-response marketing company. What this means in short, is that if you have a tangible value attached to a service or good you sell, I can make you very very rich, very very quickly. I work clients of various sizes spanning 22 countries, I have about 47 contractors at my disposal for my needs. To be more specific, when a few of my clients like Amazon or eBay want to make more money, our company is the one they come to."
I've always been confused at our industry being confused at how to label ourselves. Ain't no different than slinging penis pills or anything else. Know your target, see from their perspective, arrange your verbiage and copy in a way that they can connect with your reality and impress the fuck out of them in the first place.
I run an "online marketing company". 100% truth, easy to understand. People usually stop the questions after that.
+1 for the online marketing company. If there are more questions to come, you manage advertising campaigns on websites on clients behalf and get a commission of the revenue generated by customers buying their products via the advertisements you placed / managed.
depends on who's asking. if it's a chick i say i sell porn memberships, it opens up ALOT of "tensed" conversations after that because she's intrigued, and it allows you to talk about sex openly
Yep, I'm also with either "Online Marketing Company" or "Online Marketing Consultancy".
Of course, I also then get to say "...for half the time, and I make animated films for the other half", which usually means people are more interested in the films...
I just say internet marketing with a straight face like it's the most obvious thing ever and generally they stop asking 
I usually end up just saying I do web design, it's a lot simpler that way (lol). I don't like the questions or trying to explain what we do.
Ryan Eagle in disguise?
But yeah, depends on who I'm talking to, if it's just some person asking me I usually say web design so they stop asking me.
If it's a banker or so I also go the online marketing company route, and say that my company helps other companies to sell their products online.
I say online advertising and it usually stops there but some people think you have a magic or a secret get rich quick thing but I tell them it takes lots of hard work nothing's easy
haha love the responses! will definitely use some of these thanks!