Consider your resources. If your website traffic has been increasing by 10 percent with blogging alone but you’re now going to start investing in pay-per-click (PPC) ads, you can expect an increase that correlates with the additional spend. If you’re a B2B company, you can expect about a 2.5 percent click-through rate for your ads. The cost of PPC ads is based on the keywords you’re bidding on, who else is bidding on them and how relevant your ads are (known as your quality score). A marketing agency with expertise in demand generation will be able to recommend a budget and set realistic expectations for website traffic based on that budget.
Having large groups of content that all revolve around the same topic will build more relevance around keywords that you're trying to rank for within these topics, and it makes it much easier for Google to associate your content with specific topics. Not only that, but it makes it much easier to interlink between your content, pushing more internal links through your website.
That’s true Thomas – this can happen when going after very competitive keywords. To avoid that you can just grab the first subpage you see ranking – subpages most of the time won’t have a lot of brand searches associated with them/you’ll see true topic value. It may be lower than normal, but in general can’t hurt to have a passive calculation when making arguments of what you might achieve.