Keywords that produce tens of thousands of visitors or more for top 10 rankings are almost always highly competitive. Other webmasters very experienced in SEO techniques target these keywords, and often times they use "black hat" techniques that are hard to compete with. In some cases, the only way to beat them is to join them.
Still, high volume keywords are not untouchable. One SEO strategy is simply to concentrate on the highest volume keywords and play the feast or famine game. You feast when you obtain the top 10 ranking, but you starve during other times because you place so much effort into that one particular keyword phrase that you don't receive traffic for other phrases.
The downside to the High Volume / High Competition keyword strategy is that you can always count on someone trying very hard to knock you down. You can also count on those people having access to more resources than you do, because in such a high competition market there are always three types of competition - the big money players who can outspend you, the really smart guys who simply have more knowledge about SEO than you do, and then there are the slimeballs who will work every black hat trick in the book to gain that top spot - including doing things like attacking your site directly and indirectly, attacking your revenue resources, and stealing your website content.
The upside to gaining that high ranking is that you can literally multiply your visitor count by thousands of percentage points and potentially your revenue as well. You can also untap many more revenue resources if your daily visitor count is extremely high.
Like all SEO techniques, visitor retention is a big concern. If you drop out of the rankings, you still want to maintain a high visitor count. What is a good retention rate? A decent rule of thumb is that your repeat visitors should equal your daily search engine visitors on a month behind basis. So if you received 20,000 daily visitors from the search engines last month, you should receive 20,000 daily return visitors. This may seem lofty, but think about it like this: Last month you had a chance to put your site in front of roughly 600,000 people. You are only asking yourself to convert 3.5% of those people into daily visitors. The retention capabilities of your site do of course depend on the kind of site you have - community driven sites and daily news/updates sites can retain visitors much easier than can a site solely focused on selling a particular niche product - especially if that niche product is a once in a blue moon purchase like an excersise machine.
What is a good visitor retention rate for your particular niche and type of site? Only you can answer that question, and your answer is really either going to be a blue answer or a brown answer. (The blue answers you pull out of the sky, the brown answers are pulled out of your... well, you get the point). Watch your retention numbers, and make efforts to try to improve them - most especially if you are in a high volume / high competition keyword marketplace.
Talk About Attacking High Volume / High Competition Keywords
