People display two broad classes of information-seeking behavior. Known-item behaviors happen when a person is looking for a specific item they already know exists: searching for a known item, browsing directly to a known item's location, returning to an item found before, or seeking an update to something they already track. Exploratory behaviors happen when a person doesn't know exactly what they need: exploratory browsing, where they discover things serendipitously; exploratory searching, where they try various queries and refine as they go; and the integration of the two, where people alternate between searching and browsing within the same session.
These behaviors depend on specific, distinct IA support. Known-item behaviors rely heavily on accurate labeling and reliable search. Exploratory behaviors rely on strong navigation, related-content links, and good information scent throughout.
A redesign that quietly breaks known-item behaviors, by renaming a category or removing a feature users relied on, can look fine in a walkthrough and still cause a wave of support tickets the week it launches.
1: Searching for known items. Users who already knew what they wanted relied on search from wherever they landed. Removing it from interior pages breaks this behavior directly, they now have to navigate back to the homepage just to search, which many won't realize they need to do.
2: Returning to known items. A bookmarked link is the clearest expression of this behavior, the user found something valuable once and expected to return to that exact location. Removing the URL without a redirect breaks the return path entirely.
The third complaint, not wanting to scroll through everything to find a specific section, describes browsing to find a known item. Before the redesign, the browse tree let users drill down directly to the exact page they needed without reading through unrelated content. The long-scrolling page structure removed that direct path and replaced it with a format that only supports reading everything in sequence, which serves nobody who already knows what they're looking for.Reasonable fixes include restoring a persistent, sitewide search bar; implementing redirects for every changed URL so bookmarks and external links continue to work; and adding an in-page table of contents with anchor links on the long-scrolling pages, so users can jump directly to a section without scrolling past everything else. None of these fixes require reverting the redesign entirely, they specifically target the known-item behaviors that got broken along the way.