I know the game some people play with LinkedIn. Once they join your network, they see your contact base and can more easily connect with your connections. For some people, that is all it is. They have no interest in myself, my company, or what I really do. They just want the LinkedIn version of a mailing list.
There are companies out there that buy lists so that they can inundate you with phone calls and emails about things in which you have no interest. It’s called spam. By giving total strangers access to your connections, you effectively allow them to spam the contacts you (hopefully) have carefully cultivated.
If someone sends me a LinkedIn request, the first thing I do is check their profile. Who are they? Do we have some commonalities? What is the business relationship? If there is no connection, I question the motives of the sender. I don’t feel obliged to automatically accept every invitation that comes my way.
LinkedIn can be a powerful too if used properly. Too many people look at it as simply a numbers game.