Accept, Deny or Do Nothing At All?

This is the question that, from time to time, I ask myself in the context of online networking.

Like many other people, my profile can be found on several online platforms, one of which I have joined primarily for business reasons, the other ones for entertainment, fun and in the hope of coming across like-minded individuals and people who give me food for thought and interesting stuff to read, or simply to search for long-lost acquaintances and friends.

Ever since I have begun venturing into and setting up these networks some 5 years or so ago, I have been relatively successful in finding what I came looking for, but there are still some aspects to the whole networking thing that I do not fully understand, one them being the reasons for some people to contact me.

You know how that works: you get a "friends request" or a "contact request" (the naming varies from platform to platform, but you get the idea), and then you decide whether to accept or deny the request - or simply not act on it at all.

On a business platform, the obvious reason for someone to contact me would be because either that person is looking for something that I can offer, or they want to offer something I am looking for (which is clearly stated in my profile).
Not so different, although more subtly, when it comes to social networking platforms.
Someone who wishes to be my "friend" (which is not really what they can be if we have never even been in touch before, let alone met in the offlline world) is maybe of the opinion that what I list as my interests, likes and dislikes in my profile matches theirs.

And yet, I do get requests on both types of platforms that, at least at first sight, do not show any obvious reason for getting in touch with me: our business areas do not overlap at any point, and there are no common interests, taste in music or other such things.

Sometimes, I reply to the requestor, asking them in a friendly and polite manner (yes, I can be both, if necessary!) to give me at least one reason for their request.
More often than not, there is no reply. Ever. To me, that was that then, and after about a week or so, I delete the request.
In other cases, the people thus asked have replied in such pissed-off tone (which was really not necessary), putting into question my own motivation for being part of such a network.
But does it automatically mean I have to be "friends" with each and everyone on such a platform, only because I decided to join a network and create my own part of it?
Not to me, it doesn't.

That many of the requestors have not even bothered to look at my profile properly is evident to me. How else can I explain that I get requests to be "friends" with some heavy metal band or other, when NOTHING in my profile lets anyone believe I am into heavy metal? (This, of course, just being an example. You could replace "heavy metal" with "cooking", "football", "cars", "celebrities" and many other subjects I am not interested in.)
So, if they can't be bothered to look, why have they contacted me?
Are they merely collecting contacts, taking pride in the sheer number that sits next to their name?
If that is the case, then, thank you very much, I politely decline from being just another number.
Do nothing at all seems to be the worst option. I don't particularly like it myself when I am trying to get in touch with someone and all I get as a response is... nothing.

(See http://www.blogger.com/posts.g?blogID=1949425054295660529 )