The perpetually declining cost of data storage has made our lives, especially the online versions of them, more savable and searchable than ever before. Server farms are growing faster than strawberries on FarmVille, with demand for data storage doubling every 18 to 24 months. But exactly what are we saving? Along with Google’s mission to archive and organize every bit of information in the world and Wikipedia’s quest to wrangle humanity’s knowledge into a single searchable database, startup Silentale aims to store every digital conversation that you have. Ever.

Founded by a Paris-based French Canadian, Silentale is an aggregator for your life, or at least the increasingly large part of it that streams across the inter-tubes. But rather than archiving your blog comments or flickr posts, Silentale archives only “digital conversations,” meaning basically anything that can be construed as a dialogue with others: Twitter, Facebook, email, and even SMS messages sent via your phone. Any attachments riding along with your messages are archived too, and eventually that content will even be searchable as well.

The idea is to organize the disjointed dialogue that takes place across various Internet and phone networks. A Firefox extension watches you while you watch others; go to a friend’s Facebook or LinkedIn profile and Silentale will pull up that person’s contact info and shared correspondence from your archive, not just from the network you’re viewing, but SMS messages, emails and tweets as well. The address book function pulls in all your contacts across all networks and eliminates duplicates automatically, creating a single channel for each of your contacts’ many profiles. Click on one name, and get every bit of correspondence you’ve shared across several platforms organized into a chronological timeline to create a seamless dialogue.

Sound cool? It is, for a variety of reasons. For one, being able to search through all your social nets, email, and SMS for a particular phone number, link, or business contact is a tantalizing prospect given that many Web 2.0-ers have spread their online personas across several platforms. The ability to mesh mobile communications like SMS with our Web correspondence also allows for a higher degree of organization for our many digital missives; as smartphones proliferate, it makes sense that we begin blending our phones’ functions with our computers’ in a meaningful way.

But aggregators like Silentale also raise serious privacy concerns. So much information concentrated in a single place could create a data thief’s bazaar. Further, once users give access to all their online correspondence to a single source for archival purposes, there’s no going back. A collective gasp went up recently from privacy advocates when it was discovered that two popular child monitoring software packages, Sentry and FamilySafe, are selling information gleaned from children’s private chats via Yahoo, MSN Messenger, or AOL Instant Messenger to market researchers. When all your correspondence is archived, the temptation to tap that information by means legal or not will be great.

Silentale’s private beta is underway now. The beta is free, but once the site goes public it will likely employ a freemium model that keeps up to two months of correspondence for free, with a paid option (rumored to be about $50 USD per year) to archive dialogue going back further.