I do not accept friend or contact requests from current or former clients on my personal social networking sites. Adding clients as friends may compromise your confidentiality and our privacy. I have a Facebook Page and Twitter account for my professional practice to allow people to share my blog posts, updates, etc. with other users.
I will accept followers on these pages. However, I will never acknowledge anyone as whether they are a client and I would encourage you do the same. These social media venues are resources that I use to get helpful information out.