OtherInbox, an Austin-based e-mail organization startup, has raised $2.3 million in a round of funding, according to an SEC filing. The company’s tool helps users manage their inboxes, in part by taking non-personal e-mail—like social networking site alerts, newsletters, and payment reminders—and sending them to users in digest form. It works with Gmail, Yahoo (NSDQ: YHOO), Hotmail and other e-mail providers. The company claims 100,000 users. I reached out to OtherInbox for comment earlier today but did not hear back. It’s among a growing number of startups trying to help manage e-mail overload. Others include Paul Allen-backed Gist and Xiant, along with Xobni.