Twitter faces a charge of patent infringement from IBM in the midst of its quest to go public. In an amendment to its recent S1 document filed with the Securities and Exchange Commission, Twitter revealed that IBM has accused it of violating three patents. The patents in question are: U.S. Patent No.6,957,224 - Efficient retrieval of uniform resource locators; U.S. Patent No. 7,072,849 - Method for presenting advertising in an interactive service; and U.S. Patent No. 7,099,862 - Programmatic discovery of common contacts. For now, Big Blue is open to resolving the violations without the help of the courts, inviting Twitter to "negotiate a business resolution of the allegations." But Twitter may not give up so easily.