Does many unique pages mean better SERP position?

[nycdwellers]

My site has about 50 pages. All of them are unique 500-700 word articles. Almost every page is on its keyword at the 4-8 position in google/yahoo/bing.

I can add a lot of relative unique pages on my site, about 100-200 word content per page. They all will be unique, with unique description and title. I can make about 1000+ pages.

Would you suggest me to do this? Will this action boost my SERP position.

Do more pages mean better SERP position?

[RyanKent]

You could take that approach, but I wouldn't necessarily recommend it.

In most cases, 100-200 words is not enough to represent great content. It is possible, but I don't think it is realistic for 1000 pages. Even dictionary pages offer more content.

With that said, if your pages attract attention (i.e. you get users to those pages and they link to or Like/Tweet/+1), then those pages can help improve the SERP of your other pages through good anchor text.

I would suggest a lot of caution here because you risk lowering the overall quality of your site. I would prefer a 50 page site with good content over a 1050 page site with 50 good pages and 1000 low quality pages. No one wants to wade through the bad pages to find the good ones.

[GeorgeDavis]

More pages doesn't always mean better SERP position.  There is no black and white answer on this.  Here is a helpful excerpt from a recent blog by Dr. Pete :

A common example is when you take a page of content and spin it off across 100s of cities or topics, changing up the header and a few strategic keywords. In the old days, the worst that could happen is that these pages would be ignored. Post-Panda, you risk much more severe consequences, especially if those pages make up a large percentage of your overall content.

Another common scenario is deep product pages that only vary by a small piece of information, such as the color of the product or the size. Take a T-shirt site, for example – any given style could come in dozens of combinations of gender, color, and size. These pages are completely legitimate, from a user perspective, but once they multiple into the 1000s, they may look like low-value content to Google.

The Solution

Unfortunately, this is a case where you might have to bite the bullet and block these pages (such as with META NOINDEX). For the second scenario, I think that can be a decent bet. You might be better off focusing your ranking power on one product page for the T-shirt instead of every single variation. In the geo-keyword example, it’s a bit tougher, since you built those pages specifically to rank. If you’re facing large-scale filtering or devaluation, though, blocking those pages is better than the alternative. You may want to focus on just the most valuable pages and prune those near duplicates down to a few dozen instead of a few thousand. Alternatively, you’ve got to find a way to add content value, beyond just a few swapped-out keywords.

Source

In your case, if you are able to truly make pages that are unique, valuable, and genuinely helpful to users, you definitely stand  to benefit your overall traffic.  However, If I were in your position I would focus on making more like 50-100 pages with better, higher quality content, rather than 1000's of pages with just a little content.