This is just a brief intro to the combinations of products that we use, with some of the videos that are routinely prescribed to new project team members who might not be used to the platforms or wiki based approaches to distributed collaboration.
Step 1. Crawl - WIKI Work 1.0
Wiki-based working is perhaps one of the biggest things people take some getting used to, getting a feel for how multi-authored content is created, versioned and shared. It's different to old-school Word processing/FileNetwork saving, but still has all that's needed to create the thing that's important - content - with the right amount of formatting options to enhance content without the complexity of 'feature bloat'. Confluence 5 has just been released as well, which is better than its ever been for creating, planning, editing and managing content, whilst staying informed about team updates in the activity stream.
Step 2. Walk - MashUPS
We routinely use a couple of other products in project based Confluence workspaces:
TeamCalendars - This helps display and get all scheduled project activity visible more easily, across the project team. It's been great to see this product evolve to the point where it could replace plugins such as the Gantt view plugin for Jira - now I can generate a dynamic project timeline of key project deliverables and overlay team availability, key business events and hook into JIRA for more detailed views. Whilst this is possible with internal scheduling tools, try doing that easily across multiple collaborating organisations!
HipChat - we regularly find ourselves working across a range of Enterprise Social products in our collaborations, including Yammer, Tibbr, MSLync, Skype. Sometimes it's nice to stick with simple, time limited Instant Messaging, so we use HipChat pretty regularly for Project based chats where we need to bounce an idea around quickly. However, we're still big fans of Tibbr for the big jobs in larger teams, have worked in sites where Confluence+Jira+Tibbr are integrated nicely as a next step up..