Lately I have noticed several of the people that I do design work for requesting me to design/add links off their websites to their various social networking pages.
It seems like lately, every website you visit has these links somewhere on their homepage at least. They are extremely easy to setup and execute, but what is the ultimate advantage of connecting with end users?
You connect with users on the sites they already are frequenting regularly. You do not have to try and pull them away from sites that they are on to display your company's message.
It adds a level of professionalism if you are present in all the normal venues that other company's are using.
WHAT IT WON'T DO
These pages aren't going to help your search engine results by adding in-bound links (the popular method google uses to determine page rank). These pages aren't going to send consistent traffic by just being present on the internet. These pages will not spark interest in end-users by existing.
Having these pages can't really hurt you. That being said, it won't really help you unless there is real content on these various pages and profiles that is interesting and engaging to the end users.
In my personal experience, I have only facebook fanned one company that has made their presence known after adding.I became a fan of "Slurpees". They regularly insert well-written, status into my facebook "feed" with a humorous edge. Since I do actually like Slurpees, it often catches my eye when they do updates.
Unless you are a top-wanted brands (i.e. - Prada, Louis Vuitton), just throwing up some pages on social networking is not going to help you at all. Just adding a link on your homepage is probably not going to help you that much even. If you want to connect with people on their typical sites, you are going to need to invest time to develop interesting content and really promote your social networking pages.