Community is built up in product and subject areas which in turn are divided into different types of content within that area. You have the ability to adjust the scope of the search before and after searching.
By default, the search is "from here and down" meaning all content that you have access to from where you are in the stucture and anything below.
For example, if you areat the knowledgebase in an area, the search engine is automatically set to search within those knowledgearticles. If you want to search a little wider than where you stand, select this in the menu to the left of the search field.
When you start writing, there will be suggestions for content you may be looking for. The various icons tell if the content is from a forum, knowledgebase, idea or news. You also see which area the autosuggests come from.
Search result page
In the search result you can choose to change your filters by location, author, date, whether the content contains video etc. Blue "buttons" show active filters, these can be removed.
In addition, you can sort by best match, date etc.