15. A computer system for performing context based document searches comprising: a processing unit coupled to a computer storage medium, the computer storage medium having stored thereon a plurality of computer software components executable by the processing unit, the computer software components comprising a grid builder, a content tag assignment mechanism, a feature association mechanism, a user event tracker, and a keyword matching mechanism: the grid builder constructs a content space grid comprising content tiles, each of the content tiles is associated with feature vectors and is arranged according to subject matter of words or word phrases represented by the feature vectors, wherein the feature vectors of each of the content tiles are related to a position of the content tiles on the content space grid, and wherein the position ensures that the content tiles shared a common boundary in the content space grid have related words or word phrases associated therewith; the content tag assignment mechanism assigns a content tag to each of the content tiles according to the feature vectors, wherein the content tag is assigned to each of the content tiles, respectively, and identifies locations of the content tiles within the content space grid; the feature association mechanism assigns a series of feature values for a document according to a content therein, associating the document with one or more content tiles by comparing the series of feature values for the document against the feature vectors of the content tiles, and assigning the content tag to the document based on the content tiles associated therewith based on the comparison; the user event tracker maintains a history of user events that indicates documents by updating content tags corresponding to each content tile and selecting the content tags corresponding to user preferences; and the keyword matching mechanism matches a content tag appended to a search query with a document, wherein matching comprises comparing the content tag appended to the search query against the content tag assigned to each of the one or more content tiles to find at least one corresponding content tile and to identify the document associated therewith.
15. A computer system for performing context based document searches comprising: a processing unit coupled to a computer storage medium, the computer storage medium having stored thereon a plurality of computer software components executable by the processing unit, the computer software components comprising a grid builder, a content tag assignment mechanism, a feature association mechanism, a user event tracker, and a keyword matching mechanism: the grid builder constructs a content space grid comprising content tiles, each of the content tiles is associated with feature vectors and is arranged according to subject matter of words or word phrases represented by the feature vectors, wherein the feature vectors of each of the content tiles are related to a position of the content tiles on the content space grid, and wherein the position ensures that the content tiles shared a common boundary in the content space grid have related words or word phrases associated therewith; the content tag assignment mechanism assigns a content tag to each of the content tiles according to the feature vectors, wherein the content tag is assigned to each of the content tiles, respectively, and identifies locations of the content tiles within the content space grid; the feature association mechanism assigns a series of feature values for a document according to a content therein, associating the document with one or more content tiles by comparing the series of feature values for the document against the feature vectors of the content tiles, and assigning the content tag to the document based on the content tiles associated therewith based on the comparison; the user event tracker maintains a history of user events that indicates documents by updating content tags corresponding to each content tile and selecting the content tags corresponding to user preferences; and the keyword matching mechanism matches a content tag appended to a search query with a document, wherein matching comprises comparing the content tag appended to the search query against the content tag assigned to each of the one or more content tiles to find at least one corresponding content tile and to identify the document associated therewith. 16. The computer system of claim 15 , further comprising a search query modification mechanism to identify a content tag and to modify the search query to include the identified content tag.