SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* RAMIUS CAPITAL GROUP LLC (Last) (First) (Middle) 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol S1 CORP /DE/ [ SONE ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 08/16/2007
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, $.01 Par Value	08/16/2007		P		10,000	A	$7.0976	1,118,421	I	By Parche, LLC(1)
Common Stock, $.01 Par Value	08/16/2007		P		52,500	A	$7.0976	4,775,124	I	By Starboard Value and Oppr. Master Fund(2)
Common Stock, $.01 Par Value								865,553	I	See Footnotes(3)(4)(5)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* RAMIUS CAPITAL GROUP LLC (Last) (First) (Middle) 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Starboard Value & Opportunity Master Fund Ltd (Last) (First) (Middle) 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Parche, LLC (Last) (First) (Middle) 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* C4S & CO LLC (Last) (First) (Middle) 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 19917 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* COHEN PETER A (Last) (First) (Middle) C/O RAMIUS CAPITAL GROUP, LLC 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* SOLOMON JEFFREY M (Last) (First) (Middle) C/O RAMIUS CAPITAL GROUP, LLC 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* STARK MORGAN B (Last) (First) (Middle) C/O RAMIUS CAPITAL GROUP, LLC 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* STRAUSS THOMAS W (Last) (First) (Middle) C/O RAMIUS CAPITAL GROUP, LLC 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* RCG STARBOARD ADVISORS, LLC (Last) (First) (Middle) 666 THIRD AVENUE, 26TH FLOOR (Street) NEW YORK NY 10017 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Consists of Shares owned directly by Parche, LLC (Parche). As the managing member of Parche, RCG Starboard Advisors, LLC (RCG Starboard Advisors) may be deemed to beneficially own the Shares owned by Parche. As the sole member of RCG Starboard Advisors, Ramius Capital Group, L.L.C. (Ramius) may be deemed to beneficially own the Shares owned by Parche. As the managing member of Ramius, C4S & Co., L.L.C. (C4S) may be deemed to beneficially own the Shares owned by Parche. As the managing members of C4S, each of Peter A. Cohen, Morgan B. Stark, Jeffrey M. Solomon and Thomas W. Strauss may be deemed to beneficially own the Shares owned by Parche. Each of Messrs. Cohen, Stark, Solomon and Strauss, RCG Starboard Advisors, Ramius and C4S disclaims beneficial ownership of such shares except to the extent of their pecuniary interest therein.

2. Consists of Shares owned directly by Starboard Value and Opportunity Master Fund, Ltd. (Starboard). As the investment manager of Starboard, RCG Starboard Advisors may be deemed to beneficially own the Shares owned by Starboard. As the sole member of RCG Starboard Advisors, Ramius may be deemed to beneficially own the Shares owned by Starboard. As the managing member of Ramius, C4S may be deemed to beneficially own the Shares owned by Starboard. As the managing members of C4S, each of Peter A. Cohen, Morgan B. Stark, Jeffrey M. Solomon and Thomas W. Strauss may be deemed to beneficially own the Shares owned by Starboard. Each of Messrs. Cohen, Stark, Solomon and Strauss, RCG Starboard Advisors, Ramius and C4S disclaims beneficial ownership of such shares except to the extent of their pecuniary interest therein.

3. Ramius Fund III, Ltd (Ramius Fund III), Ramius Master Fund, Ltd. (Ramius Master), RCG Ambrose Master Fund, Ltd. (RCG Ambrose) and RCG Halifax Fund, Ltd. (RCG Halifax) beneficially own 33,055 shares, 569,905 shares, 128,674 shares and 133,919 shares of Common Stock, respectively. As the managing member of Ramius Advisros, LLC (Ramius Advisors), the investment manager of each of Ramius Fund III and Ramius Master, and the investment advisor of RCG Ambrose and RCG Halifax, Ramius may be deemed to beneficially own the 33,055 shares, 569,905 shares, 128,674 shares and 133,919 shares of Common Stock beneficially owned by Ramius Fund III, RCG Master, RCG Ambrose and RCG Halifax, respectively.

4. (continuation of previous footnote) As the managing member of Ramius, C4S may be deemed to beneficially own the 33,055 shares, 569,905 shares, 128,674 shares and 133,919 shares of Common Stock beneficially owned by Ramius Fund III, RCG Master, RCG Ambrose and RCG Halifax, respectively. As the managing members of C4S, each of Peter A. Cohen, Morgan B. Stark, Jeffrey M. Solomon and Thomas W. Strauss may be deemed to own the 33,055 shares, 569,905 shares, 128,674 shares and 133,919 shares of Common Stock beneficially owned by Ramius Fund III, RCG Master, RCG Ambrose and RCG Halifax. Each of Messrs. Cohen, Stark, Solomon and Strauss disclaims beneficial ownership of such shares of Common Stock except to the extent of their pecuniary interest therein.

5. Except for Messrs. Cohen, Stark, Solomon and Strauss who have disclaimed beneficial ownership above, each Reporting Person disclaims beneficial ownership of these securities except to the extent of its pecuniary interest, and this report shall not be deemed to be an admission that any Reporting Person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.

	By: Ramius Capital Group, L.L.C.; By: C4S & Co., L.L.C., as managing member; By: /s/ Jeffrey M. Solomon, Authorized Signatory	08/20/2007
	By: Starboard Value and Opportunity Master; By: RCG Starboard Advisors, LLC, its investment manager; By: Ramius Capital Group, L.L.C., its sole member; By: C4S & Co., L.L.C., as managing member; By: /s/ Jeffrey M. Solomon, Authorized Signatory	08/20/2007
	By: Parche, LLC; By: RCG Starboard Advisors, LLC, its managing member; By: Ramius Capital Group, L.L.C., its sole member; By: C4S & Co., L.L.C., as managing member; By: /s/ Jeffrey M. Solomon, Authorized Signatory	08/20/2007
	By: C4S & Co., L.L.C.; By: /s/ Jeffrey M. Solomon, authorized signatory	08/20/2007
	By: /s/ Jeffrey M. Solomon, as Attorney in Fact for Peter A. Cohen	08/20/2007
	/s/ Solomon, Jeffrey M.	08/20/2007
	By: /s/ Jeffrey M. Solomon, as Attorney in Fact for Morgan B. Stark	08/20/2007
	By: /s/ Jeffrey M. Solomon, as Attorney in Fact for Thomas W. Strauss	08/20/2007
	By: RCG Starboard Advisors, LLC; By: Ramius Capital Group, L.L.C., its sole member; By: C4S & Co., L.L.C., as managing member; By: /s/ Jeffrey M. Solomon, Authorized Signatory	08/20/2007
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.