I never heard of the 300 word rule. My portfolio page and two other domains I have do not have any words at all, they are just big images but are certainly indexed.

But short is good. 300 words seems long unless the content is incredibly compelling.

Google's own home page contains only 30 words. Why would they consider pages with few words unworthy?

Google will index pages with less than 300 words. I would not trust the source of that information. There is no sweet-spot in terms of number of words that Google likes the most.

When trying to figure out how long you would want the page, think about the user. When optimizing for SEO, you will want to keep content in mind. A good user experience will help to build links and improve conversion.

MarketingExperiments has http://bit.ly/aATmxj this which seems to favor long copy, but gives a long explanation of factors to consider and how testing is important.

Was there any reference to the source behind the recommendation?

Thanks,

Nick Van Weerdenburg

In testing our own landing pages, the best conversions for us come from pages with a 3 line attention grabber...with either video and opt form or just opt form alone.

I'm not sure if less raises the curiosity level but this is what works for me in my industry. The best thing you can do is split test and use the one with the higher conversion. Because you can talk in "theory" all day but the proof is always in the test.

This landing page now has close to 80% conversion. Now I do them all this way but again you must test for your product/service and industry.