Deleting the dead links to your eHow articles after you move them is IMPORTANT to keep eHow from unfairly competing with your moved articles if you want the relocated articles to rank well in search engines. One of eHow’s favorite tactics (and most unethical) is to compete against its own members. You can fight back.
When you delete your articles from eHow, they can step this unfair competition up a notch by redirecting your old link to either a list of their prepaid articles or to a (very) similar, prepaid article that they no longer have to pay residual earnings on.
eHow keeps the age of your URL and any backlinks you created that are out of your control to redirect or delete. The net effect is that your article, which hopefully you have moved to a legitimate residual income site, is going to have trouble unless you let Google know that the original is gone.