22. A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by an electronic device with a display and a touch-sensitive surface, cause the device to: concurrently display a plurality of snippets of text including a first snippet of text and a second snippet of text, wherein: the first snippet of text includes first displayed snippet text corresponding to a first portion of text from a document associated with the first snippet of text; and the second snippet of text includes second displayed snippet text corresponding to a second portion of text from a document associated with the second snippet of text; detect a first gesture associated with the first snippet of text, wherein detecting the first gesture includes detecting a first contact and a second contact on the touch-sensitive surface and detecting movement of the first contact relative to the second contact on the touch-sensitive surface; and in response to detecting the movement of the first contact relative to the second contact: modify the first snippet of text to include an additional portion of text from the document associated with the first snippet of text that was not included in the first displayed snippet text, wherein the additional portion of text from the document associated with the first snippet of text includes: additional text that occurs prior to the first displayed snippet text in the document associated with the first snippet of text; and additional text that occurs after the first displayed snippet text in the document associated with the first snippet of text; and maintain display of the second snippet of text without adding any additional text from the document associated with the second snippet of text to the second snippet of text.
22. A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by an electronic device with a display and a touch-sensitive surface, cause the device to: concurrently display a plurality of snippets of text including a first snippet of text and a second snippet of text, wherein: the first snippet of text includes first displayed snippet text corresponding to a first portion of text from a document associated with the first snippet of text; and the second snippet of text includes second displayed snippet text corresponding to a second portion of text from a document associated with the second snippet of text; detect a first gesture associated with the first snippet of text, wherein detecting the first gesture includes detecting a first contact and a second contact on the touch-sensitive surface and detecting movement of the first contact relative to the second contact on the touch-sensitive surface; and in response to detecting the movement of the first contact relative to the second contact: modify the first snippet of text to include an additional portion of text from the document associated with the first snippet of text that was not included in the first displayed snippet text, wherein the additional portion of text from the document associated with the first snippet of text includes: additional text that occurs prior to the first displayed snippet text in the document associated with the first snippet of text; and additional text that occurs after the first displayed snippet text in the document associated with the first snippet of text; and maintain display of the second snippet of text without adding any additional text from the document associated with the second snippet of text to the second snippet of text. 27. The non-transitory computer readable storage medium of claim 22 , wherein a value of the redisplay threshold is related to a value of the fading threshold.