I get a CAPTCHA nearly every time answering a question on Home Improvement. I don't get that on the other SE sites. Is H.I. having above-average spam issues?
That's odd -- the code is identical, so if you are getting a lot of captchas here you should be getting it elsewhere as well.
A few things to check
avoid cutting and pasting answers (not that you would, but every time I do that, I get a captcha which is as it should be)
try logging in with a different browser in stock config (if you're a Firefox person, try Chrome.. if you're a Chrome person, try Firefox.. if you hate yourself, try Opera) to see if you still have issues.
Let me know if any of that helps.