Re: It only makes it easier to crack...
So you must treat the most innocuous site just as much as your most secure one since one can open the way to the other, making the strongest site only as strong as the weakest one.
What you say is true for some sites, but for others, not so. Let's take a couple of dozen of my facebook accounts for example. You'll be doing pretty bloody well to link [random realistic-sounding firstname] [random relistic-sounding surname] to me. Hell, I can't remember even one of the names I used on there any more, let alone passwords etc. When I want to use facebook (rare) I just create throwaway accounts as I'm sure you've seen me mention.
There are lots of other sites I've done that on. Sites where content I am desperate enough to view is hidden behind a login screen, I'll visit 10minutemail.com, sign up to the site using whatever random characters I type for username (or just the 10min email) and whatever I type for the password, !QAZxsw2 gets through most password strength meters and if not move one column right and try again.
I can see your point - for regular sites that you use a lot you should consider if there is a risk to your account being hit (here I'm only 12 or so votes from joining you with that silver badge, I'd hate that to be stuffed up!).
So while true some sites need thought, a lot don't. Most of the sites I've logged into/created accounts on etc are low-value and have little or no real information about me. If they get hacked, I won't even know about it, nor would I ever care. I would be unlikely to even recognise the username and have no chance of recognising the email address.
HTH, rather than shows I probably should've gone to bed an hour ago...