Adding a Directory to Successful Article Website

[alltreatment]

We are considering adding roughly 1,300 pages to a 2,300 page website within the drug rehab niche.  Our website is generating roughly 10,000 uniques from Search / month.

**Is there a way to estimate the change in traffic to the existing content on the site when we add 30-40% pages in the form of a directory?  **

**Is there a way to estimate the effect of the existing traffic and links to our newly added part of the site (the directory)? **

[AndieF]

Why are you planning on adding so many pages? What's the benefit for a user?

Directories are pretty frowned upon generally.

[alltreatment]

The site actually currently links outwards to a number of different state specific sites which act as a directory. We would essentially be bringing these sites under the same umbrella and creating a similar user experience. Given the drug and alcohol related article content, including a directory of drug and alcohol treatment centers is a relatively logical decision.

It's also partially a business decision as in our experience, the directory portion of the site converts users far better than article content into leads.

One option if adding that many pages is too much... Scaling back the number of pages added in the directory and slowly adding more over time.

[KristinaKledzik]

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