10. A system comprising: a mobile device network; a plurality of mobile devices configured to take digital images, connect to the mobile device network, and transmit the digital images over the mobile device network; one or more computers configured to receive the digital images from the mobile devices, apply optical character recognition to extract words from the digital images, index the digital images based on the extracted words, and store the digital images for later retrieval based on received search terms; wherein the one or more computers are configured to receive indications of document type along with the digital images, select between at least two dictionary based language models according to the indications of document type, and post-process the extracted words in accordance with the selected dictionary based language model; and wherein an indication of document type comprises a user specified category selected from a group including business cards and credit card receipts.
10. A system comprising: a mobile device network; a plurality of mobile devices configured to take digital images, connect to the mobile device network, and transmit the digital images over the mobile device network; one or more computers configured to receive the digital images from the mobile devices, apply optical character recognition to extract words from the digital images, index the digital images based on the extracted words, and store the digital images for later retrieval based on received search terms; wherein the one or more computers are configured to receive indications of document type along with the digital images, select between at least two dictionary based language models according to the indications of document type, and post-process the extracted words in accordance with the selected dictionary based language model; and wherein an indication of document type comprises a user specified category selected from a group including business cards and credit card receipts. 18. The system of claim 10 , wherein the one or more computers are configured to add extracted words and a pre-defined label to messages including the digital images.