Many people will tell you of their bad experiences with using Sharepoint in that they could never understand it or how to find stuff in it. Now, if you know anything about Sharepoint then you will understand that this is actually quite a contradiction because, if there's one thing that Sharepoint is designed to do, it’s make content easy to locate.
Sharepoint suffers from being too easy to install and get to get up and running. You can literally install Sharepoint and have it running and visible to your users within a couple hours. Then, from the time that you’ve switched it on, users can start adding sites and content, seemingly at random. Often companies will use this “just open the box” approach and then rely on the power of the underlying indexing service to assist people find content This usually works for a while but really doesn’t scale beyond more than a few thousand documents.
Sharepoint offers many “hooks” on which to hang content – such as Audiences, Topics and Areas. These are simple ways for users to either “locate” content or to have it actually targeted and pushed at a target audience. Using things such as Areas also allow search scopes to be defined based on those structures making the search much more effective as you can search over a narrower, more focused view of your content as opposed to always sorting through the entire content.
It’s my guess that organizations which have been plagued with bad Sharepoint experiences have done poorly with planning or implementation this essential taxonomy. For example, these sites may have merely stuck with the out of the box Areas and Topics rather than modeling them on their own business and processes. This would be a major mistake as these are the things that allow users to find things based on how they would find them naturally within your business.
Here is a link to an excellent blog post which discusses some thoughts around this very topic:
http://blogs.tamtam.nl/bart/default,date,2005-04-08.aspx