g1smd - 11:47 am on Oct 10, 2011 (gmt 0)
When a real link on another site was blatently meant to point to a page of your site but the URL is truncated or malformed, go ahead and redirect it to the right page.
Where Google has "invented" a duff URL supposedly pointing to your site from a reference in a "non-link", i.e found in a non-clickable reference on another site, I would be very wary of redirecting. You're never going to get a real visitor requesting the malformed URL because there isn't really a link pointing at the malformed URL, it's just some text on a page that Google has mis-interpreted as being a real and full URL.
Indeed, creating just such a redirect might even be a signal of "over SEO-ing" a site.
However, this is one reason why I much prefer to have the item ID as the first item in a hyphenated URL. For
www.example.com/14238229-acme-green-widget-model-e422-large, as long as the requested URL contains at least
www.example.com/14238229 the site will redirect to the correct URL. This occurs whether some or all of the slug text is missing or malformed, or there is extra junk appended on the end. If there are digits missing, the user will be redirected to the page for a different product; but at least there will be no duplicate content issues.