More than you ever wanted to know about cast iron frying pans.

Here.
Well, I mostly agree with the author.  Where we (very slightly) part ways is that he may be worrying about this stuff too much.  Cook tomatoes in my good frying pan?  Sure, did it for supper last night.  Let it soak a few hours afterward, no prob.  Then I scrubbed it with soap.  (Yes!  Soap!  Boo!)  And today I fried up a mess of pancakes today, had zero sticking problems.  I think what's getting that pan past all of this abuse is that butter is my grease of choice, with olive oil sometimes coming into play when it just seems more right for the recipe.  Sometimes (and this is really hard for me) it's just best not to over-think stuff.
But all of his stuff about drying a pan on a hot stove is spot-on.  And his explanation about how the newer pans don't have a machined surface, (a) wow, that makes sense, (b) why hadn't I heard of that before? and (c) will somebody start adding that machining step, please?  Because as smooth and planed-down by a metal spatula as my 15 year old Lodge has gotten with use, I'd love to get my hands on another nice pan.
Bottom line: don't over scrub, use plenty of good grease, and stop thinking of that black coating as something nasty to be removed.  It's a self-regenerative polymer coating that is both organic and non-toxic.  All of which is a hell of a lot more than can be said for any other non-stick pan coating.