YouSendIt Buys Email Collaboration Startup Attassa And E-Signature Service Zosh

File sharing service YouSendIt has just announced the acquisitions of email collaboration startup Attassa and e-signature service Zosh. Terms of the deals were not disclosed.

Attassa’s SDK adds a collaborative layer on top of Microsoft Outlook. Features include file-sharing, synchronization and backup service. Attassa’s nifty iPhone app, which we wrote about here, also synchronizes users’ email from Outlook and other Webmail servers. Zosh’s e-signature service, which launched at DEMO, allows users to view, fill, sign and transmit documents from a mobile phone. You can then email the completed documents as standard PDF files.

YouSendIt, which recently raised $15 million in new funding, allows users to easily send and receive files and folders as large as 2 gigabytes in size (rather than send the file itself via email, you send a link to the file that is hosted on YouSendIt’s servers). These acquisitions should help boost YouSendIt’s functionality beyond just file sharing.