I and my co-workers get into long and eventually confusing email threads about what we're working on, or comments and revisions about a certain project.
For example, I'll email several people about a design I've worked on, and everyone will respond back with their own comments and suggestions, and then everyone will respond back again with comments to the comments, etc.
Too many emails are sent this way and it's not very helpful.
Does anyone have a suggested web app, preferably free, that could help solve this problem? Ideally, multiple people could use it, we can upload files to it, make comments, easily show diffs/revisions, etc. I'm less looking for a web app that handles big project collaboration (like Basecamp) - more of the day-to-day stuff.
I did google around, but I'm not sure I know for what I'm searching.
I know this isn't a question about a specific web app, but I thought I'd ask anyway.