A method in a conferencing system comprising a compere client, a participant client and a server, wherein the method comprises: a.) partitioning, by the compere client, a document into at least one page (step 201); b.) determining, by the compere client, for each of the at least one page, an identifier value, wherein the identifier value is digest information by using a digest algorithm, thereby determining at least one identifier value (step 202); c.) sending, by the compere client, a page notification message that carriers an identifier value among the at least one identifier value of a page among the at least one page to the server (step 203); d.) sending, by the server, the page notification message to the participant client (step 204); e.) if the page corresponding to the identifier value is not saved in the server, sending, by the server, a first page request message to the compere client (step 205); f.) after step e.), sending, by the compere client, the page corresponding to the identifier value to the server (step 206); g.) saving, by the server, the page corresponding to the identifier value and a correspondence between the identifier value and the page in a memory of the server (step 207); h.) if the page corresponding to the identifier value is not saved in the participant client, sending, by the participant client, a second page requesting message to the server (step 208); i.) after step h.), sending, by the server, the page corresponding to the identifier value to the participant client (step 209); j.) saving, by the participant client, the page corresponding to the identifier value and the correspondence between the identifier value and the page in a memory of the participant client (step 210). a.) partitioning, by the compere client, a document into at least one page (step 201); b.) determining, by the compere client, for each of the at least one page, an identifier value, wherein the identifier value is digest information by using a digest algorithm, thereby determining at least one identifier value (step 202); c.) sending, by the compere client, a page notification message that carriers an identifier value among the at least one identifier value of a page among the at least one page to the server (step 203); d.) sending, by the server, the page notification message to the participant client (step 204); e.) if the page corresponding to the identifier value is not saved in the server, sending, by the server, a first page request message to the compere client (step 205); f.) after step e.), sending, by the compere client, the page corresponding to the identifier value to the server (step 206); g.) saving, by the server, the page corresponding to the identifier value and a correspondence between the identifier value and the page in a memory of the server (step 207); h.) if the page corresponding to the identifier value is not saved in the participant client, sending, by the participant client, a second page requesting message to the server (step 208); i.) after step h.), sending, by the server, the page corresponding to the identifier value to the participant client (step 209); j.) saving, by the participant client, the page corresponding to the identifier value and the correspondence between the identifier value and the page in a memory of the participant client (step 210).