The fulltext search is looking for your entry in the title and description of every document. It searches also for strings with minimum three characters and doesn't pay attention on the upper and lower case.

The full text search is recommended, if you are searching for general informations. It works like the usual search of a dms. For example, if you were searching for the number “4711”, then you would see all documents which have these number anywhere in there description, no matter if it would be the number of the product or the number of the customer. So you would get a lot of documents which you were not searching for. This is why you should try to specify your search.