Private messaging through social media is nothing new - most social sites have had some sort of messaging system in place since their inception. But, to combat spambots and online lurkers, users were normally restricted to only sending messages to their friends or the people that they followed who followed them back. If you weren't connected with somebody, you couldn't message them. That, however, has changed thanks to the need to monetize social sites, and Facebook and LinkedIn both offer users the option to pay their way into an inbox. Twitter, however, remains steadfast in the older 'followers-only' model. As direct messaging is a time-tested and well-loved marketing tool, many businesses are wondering if they can take advantage of messaging through social media. The answer is yes, of course you can, but each site has its own pros and cons that you need to consider before hitting the send button.
Pros: Facebook is easily the most popular and active of the three social networks, so there is a better chance any marketing messages you send out will be seen. Some users are also used to interacting with brands through Facebook, and won't be too surprised if a rep from one of their favorite companies reaches out.
Cons: In spite of the prevalence of businesses on Facebook, it is still mainly a site people use to unwind. They want to talk with their friends, look at pictures, and play games. And even if someone interacts with your page, they will still feel a little uneasy if you reach out unsolicited and try to contact them. Businesses already tread a fine line on Facebook, and if you start messaging your followers, they aren't going to be your followers for very long. Any message you send will end up in the 'Other' folder anyway. Users in some countries can pay for access to some inboxes, but this feature is not site-wide yet and, in all honesty, it can be a bit creepy to know a business rep is tracking your personal profile.
Pros: The biggest 'pro' for Twitter would have to be the fact you can still send messages to people for free, as long as they follow you, and receive messages as long as you follow the sender. You can also send as many messages as you want, and move a conversation off of the public feed. This is especially useful in sales and customer service, where you may not want everyone watching what you are doing.
Cons: Direct messages are still limited to 140 characters, so you aren't able to really say much beyond 'e-mail us at...' And, like Facebook, Twitter is not a business-only medium, so receiving a message from a company can be a bit jarring. Twitter users do follow businesses to hear about deals and sales, but people prefer to start the conversation with a business, rather than the other way around. There also isn't a mass 'direct message' button, so you'd wind up having to go through each and every one of your followers.
Pros: The biggest pro for LinkedIn is that it is actually meant to be used for networking and business. No one that uses LinkedIn will be surprised or upset that someone representing a business sent an 'InMail' to get in contact with them, and it is more likely they will positively respond any message you send. B2B marketers can especially benefit from direct messaging through LinkedIn because LinkedIn guarantees an answer to any InMail sent. If you don't receive a response, you get your messaging credit back.
Cons: As you might have inferred from 'messaging credit,' LinkedIn's InMail costs money. If you aren't a premium member, messages will run you ten bucks a pop, and even premium members only get a set number of messages. LinkedIn also isn't as active as Facebook and Twitter, though you are more likely to effectively reach your target lead on LinkedIn
For Facebook and Twitter, the cons really outweigh the pros when it comes to direct messaging. These sites were not built with business marketing in mind, though they do lend themselves very well to it. Stick with regular social marketing tactics, build your followers, and design a campaign in which they willingly engage with you. LinkedIn, on the other hand, can lend itself quite well to direct marketing, but InMail is expensive, so make sure it is worth paying around ten bucks to contact the person you want to talk to. Depending on your business and the type of customers you serve, it can be worth reaching out using different social channels, but it is more likely that direct messaging will hurt your social presence rather than help it.