O3B NETWORKS LIMITED PREEMPTIVE RIGHTS AGREEMENT

EXHIBIT 10.51

O3B NETWORKS LIMITED

PREEMPTIVE RIGHTS AGREEMENT

      This Preemptive Rights Agreement (the “ Agreement ”) is entered into as of the 4 ^th day of January, 2008, by and among O3B N etworks Limited , a private company limited by shares organized under the laws of Jersey (the “ Company ”), LGI Ventures B.V. (the “ Preferred Investor ”), and each of the persons and entities listed on Exhibit A hereto (the “ Initial Common Investors ” and, together with the Preferred Investor, the “ Investors ”).

Recitals

      Whereas, the Preferred Investor is purchasing Series A Preference Shares of the Company (the “ Series A Preference Shares ”) pursuant to that certain Series A Preference Share Purchase Agreement (the “ Purchase Agreement ”) of even date herewith (the “ Investment ”);

      Whereas , the Preferred Investor’s entry into the Purchase Agreement is expressly conditioned upon the execution and delivery of this Agreement by the other parties hereto; and

      Whereas , in connection with the consummation of the Investment, the parties desire to enter into this Agreement in order to grant preemptive rights to the Investors as set forth below.

      Now, Therefore, in consideration of these premises and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows:

SECTION 1. GENERAL.

      1.1 Definitions. As used in this Agreement the following terms shall have the following respective meanings:

           (a) An “Affiliate” of the Preferred Investor shall mean any person or entity that directly or indirectly, through one or more intermediaries, controls, is controlled by, or is under common control with, the Preferred Investor.

           (b) “ Common Shares ” shall mean the Common Shares of the Company.

           (c) “ Non-U.S. Legal Requirements ” shall mean, in the case of a public offering or registration of any of the Company’s securities on a public securities exchange (whether regulated or otherwise) in the United Kingdom or elsewhere in the world other than the United States all applicable laws, regulations or other legal requirements necessary to permit the unrestricted sale of such securities to be registered in such jurisdiction and on such market by the Company or the Holders of such securities, as the case may be.

           (d) “ Qualified IPO ” shall mean the first firmly underwritten public offering pursuant to an effective Registration Statement under the Securities Act or Non-U.S. Legal Requirements (i) covering the offer and sale of Common Shares for the account of the Company

that values the Company at not less than €121,250,000 prior to the consummation of such offering and in which the net cash proceeds to the Company (after underwriting discounts, commissions and fees) are at least €34,750,000 (or its equivalent in U.S. dollars if such offering is effected in the United States) and (ii) after which the Common Shares are listed on the New York Stock Exchange, the Nasdaq Global Market, the Nasdaq Global Select Market or a designated offshore securities market (as defined in Regulation S under the Securities Act).

           (e) “ Registration Statement ” shall mean (i) with respect to an offering of the Company’s securities in the United States, a registration statement as defined in the Securities Act and (ii) with respect to the offering of the Company’s securities in non-U.S. jurisdictions, the comparable documents required under applicable Non-U.S. Legal Requirements for the relevant securities to be registered, listed, admitted to trading or otherwise and includes, without limitation, prospectuses, listing particulars and admission documents.

           (f) “ SEC ” or “ Commission ” shall mean the U.S. Securities and Exchange Commission.

           (g) “ Securities Act ” shall mean the U.S. Securities Act of 1933, as amended.

SECTION 2. PREEMPTIVE RIGHTS .

      2.1 Subsequent Offerings. Each Investor shall have a preemptive right to purchase its pro rata share of all Equity Securities (as defined below) that the Company may, from time to time, propose to sell and issue after the date of this Agreement, other than the Equity Securities excluded by Section 2.4 hereof. For this purpose, each Investor’s pro rata share is equal to the ratio of (a) the number of Common Shares (including all Common Shares issuable or issued upon conversion of the Series A Preference Shares or upon the exercise or conversion of outstanding warrants or options or convertible securities) of which such Investor, together with its Affiliates, is a holder or would be a holder upon conversion or exercise at the time notice of the proposed issuance of such Equity Securities is given by the Company pursuant to Section 2.2 to (b) the total number of Common Shares (including all Common Shares issued or issuable upon conversion of the Series A Preference Shares or upon the exercise or conversion of any outstanding warrants or options or convertible securities) outstanding immediately prior to the issuance of such Equity Securities. The term “ Equity Securities ” shall mean (i) any Common Shares, Preference Shares or other equity security of the Company, (ii) any security convertible into or exercisable or exchangeable for, with or without consideration, any Common Shares, Preference Shares or other equity security of the Company (including any option to purchase such a convertible security), (iii) any security carrying any warrant or right to subscribe to or purchase any Common Shares, Preference Shares or other equity security of the Company or (iv) any such warrant or right.

      2.2 Exercise of Rights. If the Company proposes to issue any Equity Securities, it shall give each Investor written notice of its intention, describing the Equity Securities and the price and other terms and conditions upon which the Company proposes to issue the same. Each Investor shall have ten (10) days from the date such notice is deemed given to exercise its right to purchase its pro rata share of the Equity Securities on the terms and conditions specified in the notice by giving written notice thereof to the Company. Notwithstanding the foregoing, the

Company shall not be required to offer or sell such Equity Securities to any Investor if doing so would cause the Company to be in violation of applicable securities laws by virtue of such offer or sale.

      2.3 Issuance of Equity Securities to Other Persons. The Company shall have ninety (90) days after the end of the aforementioned 10-day period to sell the Equity Securities in respect of which the Investor’s rights were not exercised, at a price not lower and upon terms and conditions not more favorable to the purchasers thereof than specified in the Company’s notice to the Investors pursuant to Section 2.2 hereof. If the Company has not sold such Equity Securities within ninety (90) days after the end of the aforementioned 10-day period the Company shall not thereafter issue or sell any Equity Secu