In my experience it's been that the Yahoo directory didn't help much over a long period of time in Yahoo. This was due to that the company had later changed it's products/keywords, but for a long time they were still showing up in Yahoo results for the old keywords, based on their Yahoo directory listing. Of course it didn't help a bit showing up for outdated keywords that were unrelated to their current product offerings.

That said, I've seen companies drop their listing completely from Yahoo's directory, and it made no impact whatsoever in Google or MSN.

So it may help somewhat to jumpstart a presence, but in my view it's not worth it being a long-term investment (meaning, no need to keep renewing in subsequent years).

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