So why would you use a generic invitation for someone to connect with you on LinkedIn?
Impersonal Network Requests. A generic “I’d like to invite you to join my professional network” request does not create a warm, personal connection or give the receiver any reason to accept your invite. It conveys that you couldn’t be troubled to wrote a sentence or two. Worse, the receiver might not even remember who you are! Every request should be customized, reminding the receiver of your past connection and a positive association. It only takes a few seconds and goes a long way towards building a strong connection.
Read more of the posting here http://blog.jobfully.com/2010/10/avoiding-linkedin-faux-pas/
And the next time you connect with someone on LinkedIn, make your request personal. After all it is business!