Cobwebs

Okay, can somebody please explain cobwebs to me? Do they really come from spiders? Or are they just because there is a lot of dust in your house?

I'm sitting at my computer desk. I looked up and the corner is filled with cobwebs. This is the most "cobwebby" house I have ever known. Even our previous house that was 80+ years old was not this bad. We do have a lot of spiders too! I guess it's just because of the setting in which we live.....which is kind of a crack-up because we don't live in the country or anything, but it is kind of wooded.

I think I could dust every day (but I won't) and I would still find cobwebs every day. You should see what it's like when we come home from a week-long vacation....they take over!!!!

But anyways, if anyone has comments or information on cobwebs please post it.

Editing to add: I did a search and this is what I came up with. This is pretty much everything you ever wanted to know about cobwebs...but were afraid to ask. Aren't you glad I asked for you?
http://www.straightdope.com/mailbag/mcobweb.html