3. The method of claim 2 , further comprising: in the aggregating step, aggregating the stored annotations for each of the plurality of items such that the keywords associated with the item are aggregated from all the annotations of the item; searching for one of the plurality of users based on the collaborative content relevance of the annotations associated with the one of the plurality of users and at least one search keyword associated with the searching; the collaborative content relevance established by one of: determining items whose keywords match the at least one search keyword; and determining users that annotated the determined items; and returning the determined users as the search result.
3. The method of claim 2 , further comprising: in the aggregating step, aggregating the stored annotations for each of the plurality of items such that the keywords associated with the item are aggregated from all the annotations of the item; searching for one of the plurality of users based on the collaborative content relevance of the annotations associated with the one of the plurality of users and at least one search keyword associated with the searching; the collaborative content relevance established by one of: determining items whose keywords match the at least one search keyword; and determining users that annotated the determined items; and returning the determined users as the search result. 4. The method according to claim 3 , wherein the collaborative content relevance is further established by ranking the determined items on the basis of a Information Retrieval ranking algorithm and ranking the determined users based on a correspondence between ones of the ranked determined items and ones of the determined users that annotated the items; and returning the determined users according to rank as the search result.