Slack Technologies, Inc. 500 Howard Street San Francisco, California 94105 LETTER TO STOCKHOLDERS OF SLACK TECHNOLOGIES, INC. Dear Slack Stockholder: On December 1, 2020, Slack Technologies, Inc. (which we refer to as “Slack” or the “Company”) entered into an Agreement and Plan of Merger (which, as it may be amended from time to time, we refer to as the “merger agreement”) with salesforce.com, inc. (which we refer to as “Salesforce”), Skyline Strategies I Inc. (which we refer to as “Merger Sub I”), and Skyline Strategies II LLC (which we refer to as “Merger Sub II”). The merger agreement provides for the merger of Merger Sub I with and into Slack, with Slack continuing as the surviving corporation (which we refer to as the “first merger”), immediately followed by a second merger of the surviving corporation into either Merger Sub II or Salesforce, with either Merger Sub II or Salesforce continuing as the surviving company, as applicable (which we refer to as the “second merger” and together with the first merger, the “mergers”). Slack stockholders as of the close of business on the record date are invited to virtually attend a special meeting of Slack stockholders on March 2, 2021, at 10:00 a.m. Pacific Time, to consider and vote upon a proposal to adopt the merger agreement and approve the transactions contemplated thereby, a non-binding advisory proposal to approve certain compensation that may be paid or become payable to Slack’s named executive officers that is based on or otherwise relates to the mergers, and a proposal to approve the adjournment of the special meeting, if necessary or appropriate, to solicit additional proxies if there are not sufficient votes at the time of the special meeting to adopt the merger agreement and approve the transactions contemplated thereby. Subject to the terms and conditions of the merger agreement, at the first effective time of the first merger (which we refer to as the “first effective time”), each outstanding share of Slack Class A common stock and Slack Class B common stock (other than shares of Slack common stock owned directly or indirectly by Salesforce, Slack or any of their respective subsidiaries immediately prior to the first effective time, shares of Slack common stock as to which dissenters’ rights have been properly perfected, and shares of Slack common stock covered by Slack restricted share awards) will be converted in the first merger into the right to receive 0.0776 shares of Salesforce common stock and the right to receive $26.79 in cash, without interest (which we refer to as the “merger consideration”). Based on the closing price of Salesforce common stock on November 24, 2020, the last full unaffected trading day before the first published rumor regarding a potential merger transaction, the value of the per share merger consideration payable to holders of Slack common stock upon completion of the first merger was approximately $47.03. Based on the closing price of Salesforce common stock on January 28, 2021, the last practicable date before the date of the proxy statement/prospectus accompanying this notice, the value of the merger consideration payable to holders of Slack common stock upon completion of the first merger was approximately $44.37. Slack stockholders should obtain current stock price quotations for Salesforce common stock and Slack common stock. Salesforce common stock is traded on the New York Stock Exchange under the symbol “CRM,” and Slack common stock is traded on the New York Stock Exchange under the symbol “WORK.” The Slack board of directors has unanimously determined that the merger agreement and the transactions contemplated by the merger agreement, including the mergers, are fair to, and in the best interests of, Slack and its stockholders; has unanimously approved and declared advisable the merger agreement and the transactions contemplated thereby, including the mergers; and unanimously recommends that Slack stockholders vote “FOR” the adoption of the merger agreement and “FOR” the other proposals described in the accompanying proxy statement/prospectus. Slack will hold a virtual special meeting of its stockholders to consider certain matters relating to the mergers. Salesforce and Slack cannot complete the mergers unless, among other things, Slack stockholders adopt the merger agreement and approve the transactions contemplated thereby. Your vote is very important. To ensure your representation at the special meeting, complete and return the applicable enclosed proxy card or submit your proxy by phone or the Internet. Please vote promptly whether or not you expect to virtually attend the special meeting. Submitting a proxy now will not prevent you from being able to vote at the special meeting. The proxy statement/prospectus accompanying this notice is also being delivered to Slack’s stockholders as Salesforce’s prospectus for its offering of shares of Salesforce common stock in connection with the mergers. The obligations of Salesforce and Slack to complete the mergers are subject to the satisfaction or waiver of the conditions set forth in the merger agreement, a copy of which is included as part of the accompanying proxy statement/prospectus. The proxy statement/prospectus provides you with detailed information about the mergers. It also contains or references information about Salesforce and Slack and certain related matters. You are encouraged to read the proxy statement/prospectus carefully and in its entirety. In particular, you should carefully read the section entitled “Risk Factors” for a discussion of risks you should consider in evaluating the mergers and the issuance of shares of Salesforce common stock in connection with the mergers and how they will affect you. Sincerely, Stewart Butterfield Co-Founder, Chief Executive Officer and Chairperson of the Board of Directors Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued under the accompanying proxy statement/prospectus or passed upon the adequacy or accuracy of the disclosure in this document. Any representation to the contrary is a criminal offense. The proxy statement/prospectus is dated January 29, 2021 and is first being mailed to stockholders of Slack on or about January 29, 2021. Slack Technologies, Inc. 500 Howard Street San Francisco, California 94105 NOTICE OF THE SPECIAL MEETING OF STOCKHOLDERS TO BE HELD VIRTUALLY VIA THE INTERNET ON MARCH 2, 2021 Notice is hereby given that a special meeting of stockholders of Slack Technologies, Inc. (which we refer to as “Slack”) will be held on March 2, 2021 at 10:00 a.m. Pacific Time via a live interactive audio webcast on the Internet (which we refer to as the “Slack special meeting”). You will be able to vote and submit your questions at www.virtualshareholdermeeting.com/WORK2021SM during the meeting. We are holding the special meeting for the following purposes, which are more fully described in the accompanying proxy statement/prospectus: • to adopt the Agreement and Plan of Merger, dated as of December 1, 2020 (which, as it may be amended from time to time, we refer to as the “merger agreement”), among salesforce.com, inc. (which we refer to as “Salesforce”), Skyline Strategies I Inc. (which we refer to as “Merger Sub I”), Skyline Strategies II LLC (which we refer to as “Merger Sub II”) and Slack and approve the transactions contemplated thereby (which we refer to as the “merger proposal”); and • to approve, by a non-binding advisory vote, certain compensation that may be paid or become payable to Slack’s named executive officers that is based on or otherwise relates to the mergers contemplated by the merger agreement (which we refer to as the “non-binding compensation advisory proposal”). Slack stockholder approval of the merger proposal is required to complete the mergers as contemplated by the merger agreement. Slack stockholders will also be asked to approve the non-binding compensation advisory proposal. Slack will transact no other business at the Slack special meeting. The record date for the Slack special meeting has been set as January 25, 2021. Only Slack stockholders of record as of the close of business on such record date are entitled to notice of, and to vote at, the Slack special meeting via the Slack special meeting website or any adjournments and postponements of the Slack special meeting. For additional information regarding the Slack special meeting, see the section entitled “Special Meeting of Slack Stockholders.” The Slack board of directors unanimously recommends that you vote “FOR” the merger proposal and “FOR” the non-binding compensation advisory proposal. The Slack proposals are described in more detail in the accompanying proxy statement/prospectus, which you should read carefully and in its entirety before you vote. A copy of the merger agreement is attached as Annex A to the accompanying proxy statement/prospectus. PLEASE VOTE AS PROMPTLY AS POSSIBLE, WHETHER OR NOT YOU PLAN TO ATTEND THE SLACK SPECIAL MEETING VIA THE SLACK SPECIAL MEETING WEBSITE. IF YOU LATER DESIRE TO REVOKE OR CHANGE YOUR PROXY FOR ANY REASON, YOU MAY DO SO IN THE MANNER DESCRIBED IN THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS. FOR FURTHER INFORMATION CONCERNING THE PROPOSALS BEING VOTED UPON, USE OF THE PROXY AND OTHER RELATED MATTERS, YOU ARE URGED TO READ THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS. Your vote is very important. Approval of the merger proposal by the Slack stockholders is a condition to the mergers and requires the affirmative vote of a majority of the voting power of all issued and outstanding shares of Slack common stock entitled to vote on the proposal. Slack stockholders are requested to complete, date, sign and return the enclosed proxy in the envelope provided, which requires no postage if mailed in the United States, or to submit their votes by phone or the Internet.