A method of adding a computerized agent to an instant messaging (IM) session managed by an IM service for identifying automatically textual instructions to perform a transaction related to participant(s) of the IM session, comprising: using a computerized agent subscribed to an IM service by a telephone number and participates in an IM session managed by an IM service to acquire text content in an IM session and analyzing at least the text content of the IM session to identify automatically textual instructions to perform a transaction from the user which uses the IM client module, automatically instructing an operation of the transaction and submitting by the computerized agent at least one IM message in the IM session.