CONVERTIBLE PROMISSORY NOTE

Exhibit 4.1

THIS CONVERTIBLE PROMISSORY NOTE AND THE SECURITIES THAT MAY BE ACQUIRED PURSUANT TO THIS CONVERTIBLE PROMISSORY NOTE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR UNDER THE SECURITIES LAWS OF ANY STATE OR OTHER JURISDICTION. THIS CONVERTIBLE PROMISSORY NOTE AND SUCH OTHER SECURITIES MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, HYPOTHECATED OR OTHERWISE DISPOSED OF IN THE ABSENCE OF A REGISTRATION STATEMENT AND LISTING APPLICATION IN EFFECT WITH RESPECT TO THIS CONVERTIBLE PROMISSORY NOTE OR SUCH OTHER SECURITIES UNDER THE SECURITIES ACT AND ANY OTHER APPLICABLE SECURITIES LAW, OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION AND LISTING ARE NOT REQUIRED PURSUANT TO A VALID EXEMPTION THEREFROM UNDER THE SECURITIES ACT AND THE APPLICABLE SECURITIES LAW OF ANY STATE OR OTHER JURISDICTION.

CONVERTIBLE PROMISSORY NOTE

FOR VALUE RECEIVED, E-centives, Inc. , a Delaware corporation (the “Company”), having an address of 6901 Rockledge Drive, 6 ^th Floor, Bethesda, Maryland 20817, hereby promises to pay to the order of US Venture 05, Inc. (the “Holder”), at the offices of the Holder at c/o Friedli Corporate Finance, Freigutstrasse 5, 8002 Zürich , or such other place as may be designated by the Holder to the Company in writing, the aggregate principal amount of Three Million US Dollar (US $ 3’000’000) together with accrued unpaid interest on the unpaid principal amount hereof, upon the terms and conditions hereinafter set forth.

1. Payment Terms . The Company promises to pay to the Holder the balance of Principal, together with Premium and accrued unpaid interest, on November 21, 2007 , unless this Note is earlier prepaid as herein provided or earlier converted into Series C preferred stock, par value US $0.01 per share, of the Company (the “ Series C Preferred Stock ”) pursuant to Section 3 hereof. All payments hereunder shall be made in lawful money of the United States of America. Payment shall be credited first to the accrued interest then due and payable and the remainder to Principal.

2. Interest . Interest on the outstanding portion of Principal of this Note shall accrue at a rate of ten percent (10%) per annum . All computations of interest shall be made on the basis of a 365-day year for actual days elapsed. Such interest shall be paid in arrears on the last business day of each successive one year anniversary of the date of this Note.

3. Conversion of this Note .

(a) Conversion . This Note shall be convertible into shares of Series C Preferred Stock at any time by the Holder at the Note Conversion Rate (hereinafter defined) as hereinafter provided. The conversion price will be US $4.00 per share of Series C Preferred Stock (the “Note Conversion Rate”). The number of shares of Series C Preferred Stock to which the Holder shall be entitled upon such conversion shall be equal to the product of: the aggregate principal amount outstanding under this Note at the time of such conversion, together with Premium and accrued unpaid interest, divided by the Note Conversion Rate.

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(b) Conversion Calculations: No Fractional Shares . Conversion calculations pursuant to this Section 3 shall be rounded to the nearest whole share of Series C Preferred Stock, and no fractional shares shall be issuable by the Company upon conversion of this Note. Conversion of this Note shall be deemed payment in full of this Note and this Note shall thereupon be cancelled.

4. Subordination . The indebtedness evidenced hereby is subordinate in right of payment to all existing and future bank indebtedness, including lease and equipment finance obligations. The indebtedness represented hereby is senior in right of payment to all classes and series of the Company’s capital stock and all debt securities issued by the Company.

5. Redemption . This Note may be redeemed by the Company at any time by payment of the entire principal and interest outstanding under this Note, plus the applicable Final Payment Amount (“Premium”) (hereafter defined), in cash to the Holder.

(a) “Final Payment Amount” means an amount equal to: (i) during the first full year of this Note, 8% of the unpaid Principal amount under this Note, (ii) from and after the first business day of the second full year of this Note, 16% of the unpaid Principal amount under this Note.

6. Representations and Warranties of the Company . The Company represents and warrants to the Holder as follows:

(a) The execution and delivery by the Company of this Note (i) are within the Company’s corporate power and authority, and (ii) have been duly authorized by all necessary corporate action.

(b) This Note is a legally binding obligation of the Company, enforceable against the Company in accordance with the terms hereof, except to the extent that (i) such enforceability is limited by bankruptcy, insolvency, reorganization, moratorium or other laws relating to or affecting generally the enforcement of creditors’ rights and (ii) the availability of the remedy of specific performance or in injunctive or other equitable relief is subject to the discretion of the court before which any proceeding therefore may be brought.

7. Representations, Warranties and Covenants of the Holder . The Holder represents and warrants to the Company, and agrees, as follows:

(a) This Note and any Series C Preferred Stock issuable upon conversion of this Note and any shares of Common Stock, par value $0.01 per share, of the Company issued upon conversion of the Series C Preferred Stock (the “Common Stock” and, together with this Note and the Series C Preferred Stock, the “Securities”) are being acquired by the Holder for its own account for investment and not with a view to, or for sale in connection with, any distribution thereof.

(b) The Holder is an “accredited investor” within the meaning of Rule 501 under the Securiti