Today I received a great question via email regarding social media etiquette. The question was this: "In the social media world, is it appropriate etiquette to follow everyone who follows me?" The question was specific to Twitter and so my answer is specific to that social media site. It is customary to follow back everyone who follows you. My exception to this standard is that I don't follow back obvious scammers, self-promoters or anyone who says, "I will get you 100k Twitter followers." Whenever I receive a new follower, I quickly look at their profile and their last three posts. If I like what I see, then I will follow them back. I will also usually send them a tweet thanking them for the follow (not a direct message aka DM) and ask them a question that pertains to the information that they have on their landing page. I have noticed that most people are not checking their @ mentions so I usually don't get a response, but I least I try to engage them without spamming them.
My personal feelings toward Twitter DM's is that I HATE THEM! Notice how I used all caps to convey strong emotion. I don't care what all of the marketers are telling you. Don't spam new followers with a DM. Send them a personal public tweet instead. I never click any of links that new followers or people I have chosen to follow send me via DM because if I did that, I'd be on Twitter all day long. Use the DM sparingly. If you want to tell someone they have an email from you, or if you want to meet up with someone then this would be a great use of the direct message feature within Twitter.
Remember that the whole point of this social media marketing thing is that you are trying to build a platform and an audience. If you don't spam people (Buy my book! Buy my product! etc.) and if you provide engaging and entertaining content, Twitter will eventually pay off for you. And don't pay someone to get you 100k followers. That's just dumb. But you're all smart enough to know that, right!?