1. A computerized method of semantically compressing structured data, the structured data defining a table, wherein the table is fully described using text and includes one or more cell elements, each cell element having a set of attribute names and attribute values that define the layout of a table cell and the structured data further comprises elements outside of the table having attribute names and attribute values, the method comprising: analyzing the structured data to identify the attribute names and attribute values in the cell elements; grouping the attribute names into an ordered set of cell attributes and assigning a name to the ordered set of cell attributes; generating an ordered set of attribute values for each of the one or more cell elements, wherein the ordered set of attribute values includes a single attribute and the attribute values and corresponds to the ordered set of cell attributes in the grouping having the assigned name; adding the ordered grouping of attribute names having the assigned name to the structured data; replacing the attribute names and attribute values of the cell elements in the structured data with the ordered sets of attribute values that includes the single attribute and the attribute values to generate a compressed version of the structured data; identifying repeated attribute names in the elements outside of the table; generating an index of the repeated attribute names, each entry in the index corresponding to a set of attribute values for the elements outside of the table; including the index in the structured data; replacing the attribute names and attribute values in the elements outside of the table with references to the index; and providing the compressed version of the structured data to a computing device, wherein the compressed version of the structured data is in a same format as the structured data.