Importance of connections: linkedin Rant

As a working sales professional, my work revolves around making connections and solving problems. that's pretty much what a career in sales is, from my perspective.
In doing so I reach out to a lot of people, which are very specific users of what services we offer, and my outreach in past few years has become very tailored to these individuals, their brands, their current market situation and how could we help.
I use LinkedIn, Twitter and email along with other mediums to reach out to people and make a connection.

Since some time I have noticed a strange phenomenon, where I have reached out to people on LinkedIn, and they have accepted and connected with me, however, they don't respond back to any greetings or specific questions asked to them. I wonder what type of connections are those?

In today's world, connections have a completely different meaning. The man is a social animal and today's business thrives on relationships & connections. However, with the advent of social media, these connections have also become quite vague.
I noticed this vagueness in my experience with linked connections. Are they accepting to connect but don't respond because they just want to expand their network? or is this the new way of being polite?
I don't know what may be in their minds, but i am pretty sure it's not helpful.

Here are some of my thoughts on how I would behave or respond, if I were moderating all of these inbound and outbound requests for connections, and things professionals should do:

1. Don't accept connections with people who you don't want to speak with or converse at this point in time.
2. If the message for outreach is tailored and specific to you, the other person is working to make it worth your time. they have put the time to write you a message, and not spamming hundreds of people. Do give it a consideration.
1. you could say that I am a big shot, and I receive hundreds of emails/solicitations every day. 
2. I say, look at those. 99% outreaches are just a bulk email. ignore those. but notice if someone is directly addressing you and your needs.
3. if you say, I still have such hundreds of such emails, then I say, don't accept their invite, don't respond to them. Simple.
3. If you accept invites from people, then engage to what level you can. Remember, connections are vital. today, you may be a customer and giving someone hard time, tomorrow, you may be working for this guy. who knows. the world is a small place and reputation is important.
4. when I have time, and I receive generic invites, I decline them immediately. For someone who seems relevant, like another sales guy at a different company,  I do write back to them asking for why do they want to connect with me.  You will note that 90% won't reply back. that itself is a sign that people just scout others and don't really think through. the ones who respond with some explanation, I often accept their connections.

So here was my short rant about connections. I believe the communication, even in the online world can be improved greatly.

What do you think about connections? your experience with Linkedin?