Welcome to the Q&A Forum

You were fairly brief, which makes it difficult to give definitive answers, but here are mine. For the first question: Are any of these new pages going to compete with currently ranking pages? If so, they could limit the traffic to existing pages. Use Google Analytics to identify your top organic keywords and check them against your new pages. Compare any new pages that might compete with existing pages; which ones do you think will win? If the new pages WON'T compete with existing pages, they will only have an effect on the Domain Authority, which should really only be a net gain. You'll have more pages, and more links overall. Last, is there any chance that this new content will trigger a penalty? I only ask this because AndieF is right, search engines don't see much value in directories, and if your site goes from 50% directory pages to 75% directory pages, the entire site may be hurt as a result. And, for your second question, about the effect of existing traffic on the new pages If the new pages are really brand new, they should be indexed faster since they're a part of an established site. To estimate the traffic they'll bring it, identify the keywords they're targeting, get the monthly traffic from Google AdWords Keyword Tool (download the list of keywords for actual previous months' traffic), and find the opportunity traffic based on how well you can reasonably expect to rank: http://geoffkenyon.com/google-serps-click-through-rates/ You mentioned in a comment that these pages are currently living on different domains, and you're moving them over. If you use 301 redirects, you'll only carry over 90 - 95% of Page Authority, but not all of it. If those links are more valuable than the new links you're providing through your site, they won't do as well. If you have some really good links to those old URLs, you may want to contact the webmasters who are sending traffic to your site and ask them to update their links. Also note that pages will take a dip in rankings whenever they get new URLs, so if you get significantly less traffic for the first couple of weeks, just wait it out. TL;DR Check: That the new pages won't compete with old pages That the new pages won't trigger a penalty from Google **The estimated searches/month (from Google AdWords Keyword Tool) for the new keywords you'll be targeting, and the proportion you can reasonably expect to get to your site (based on CTR research for Google) ** The number of links that were pointed to the pages on the old URL that you'll only get a portion of the Authority from Hope this helps! Kristina

Using the keyword 4 times instead of 2 in your body content will probably do nothing. If you simply add to your existing content and include the keyword 2 times in the new content you are adding, then yes, you could get some benefit there. But if all you do with your existing content is swap phrases, you won't change much with Google. They already know what your page is about. So the only way you could help would be to add more targeted, keyword rich content to what is already there.