I’m sure you’ll be reading in depth reviews at some point or another by your favourite blogs and super-blog sites on Backpack’s new features — but here’s the skinny. 37Signals, poster child for Web2.0 applications people actually use and pay for, has upgraded one of its first products, Backpack, yet again.

This upgrade is fairly substantial, as it allows multiple users for any given account, mimicking, in effect, a remotely-hosted “intranet”; a gathering place where you can organize notes, files, calendars, and messages. In a way, its almost like Basecamp “lite”, although it clearly does not have the heavy lifting that Basecamp has, with respect to specific project management.

The good news? People who are on the $5 / month plan are grandfathered in, while people on the $9 / month plan get a discount, to $7 / month, as they are renaming and regearing their plans (the $7 / month plan is the “Solo” plan) to take account for the number of people who might need to use your account. The highest plan is $149/ month, and 100 users, 50 gigabytes of storage, and 7500 pages.

Personally, I avoided Backpack for a long time because — well, there’s no other way to describe it — I’m cheap. Having tried it out, I can honestly say there’s nothing else quite like it. Its an all-in-one storage area for notes AND files, and other miscellania which is one hand at a moment’s notice. Its generally stable, pretty but functional, and there’s also a nice calendar system too, which I’m sure other folks find helpful.

If you’re wanting to try it out, now’s the time. Get $5 off your first month if you use the code: SVNLAUNCH.