Here is something to consider as you are connecting with key decision makers. Messages from linkedin or facebook do not frustratingly disappear nor do the messages go to a junk folder like emails. “Twenty percent of email in the United States and Canada is still not making it to the inbox while 3% of email goes to the “junk” or “bulk” folder and another 16% goes missing.” – Return Path (2010)
Some people are very good about checking their junk folder for important emails but the majority of people do not. It is time consuming to sort through all the junk. When you send something using facebook, twitter, linkedin or any other social site it is going to go straight to the person. Even though the recipient will have the option to report your message as spam (similar to email) at least the person saw the message unlike an email. Send a message using social media and be confident it will be seen.
The down side to social media as your delivery method is, of course, some people are just not using any social media sites. In these cases a great option is sending an invitation to begin using linkedin since you probably have their email. Offer to help get them set up and include your reasons for wanting to connect. Even if this method does not work at least you were more proactive in reaching out to a key decision maker or someone beneficial to your business.