Patent ID: 7747943

Claim:
A method in a computer system of anchoring an annotation to content, the method comprising: receiving an indication of a portion of the content; capturing by the computer system one or more features describing a beginning of the portion of the content; capturing by the computer system one or more features describing an ending of the portion of the content; capturing by the computer system one or more features describing a region between the beginning of the portion and the ending of the portion; generating by the computer system a histogram that identifies, for each word in the content, a frequency of occurrence of the word within the content, wherein the frequency of occurrence indicates the number of times the word appears in the content, and wherein the histogram is generated once for the content; associating by the computer system the annotation with the captured features, wherein the one or more features describing the region between the beginning of the portion and the ending of the portion comprise: an indication of one or more keywords in the region, wherein the keywords are selected by, using the generated histogram: identifying, for each word in the region, the frequency of occurrence of the word within the content, and selecting as the keywords one or more words in the region having lowest frequencies of occurrence within the content, and for each of the one or more keywords, a distance from the beginning of the portion to the keyword, and a distance from the keyword to the ending of the portion.