Having every page on your site be the exact same can strengthen your overall brand. However, it can diminish the value of the content, from a user's perspective, as they traverse your site. In this post, I'll comment briefly on the value of brand allusion.
Even in a niche market, you can have a multitude of like-branded buckets that allude to your overall brand while not creating an environment of ignorance. What do I mean by this? If you look at 10 items that have the same label, you will eventually start ignoring the label (usually by the 8th page...similar to banner blindness). However, if you allude to your brand without being redundant then you maintain the trust that your user has in your product as well as demonstrating the depth and breadth of your offering.
An example is how ebay and ebay motors are interconnected in a branding way but not in an obvious linking method. Visiting the ebay website, you see their branded logo and their standard information architecture. However, visiting their motors site, you are aware that it is ebay but the linking does not connect the parent (the parent link is offset intentionally to ensure you do not fail out of the site). This demonstrates how two sites are linked through brand allusion and not through regurgitating the same image exactly. It enables the user to clearly recognize they are not within an ebay site, but that they are on an ebay property.
