If the only server allowed for a project was a Subversion (svn) server, what would be the best way to use it as a project communication tool? For example, is there a good way that it could be used as a wiki, bug tracker, and/or blogging platform?
Note: the server is hosted by Apache, and has the basic html interface.
Subversion is a version control system, in order to have the features you ask, you will have to use a third party add-on, I recommend you to try Trac, it's an open source project management and bug tracking system for software development projects and is very easy to integrate with Subversion.
It gives you:
Check this demo site.
Subversion is great at what it does, and what it does is version source code, although it'll work well enough for other text-based formats, and binaries, with reduced capabilities.
However, as a one-stop project management tool, it falls rather short of the mark; it's far easier to track and organise bug reports and feature requests in a product that's designed to do that. Likewise, it's also far easier to use an actual wiki engine as a documentation wiki.
If you're looking for something fairly compact, you might consider Trac, as has been mentioned elsewhere, which is a decent little issue tracker/wiki/project planning tool with good source control integration.
Don't use it or come up with some bad scheme to use svn as a communications tool. Use some other wiki - there are tons out there and wherever you are hosting your svn you can put a wiki. I second Trac, by the way. It will integraee nicely with svn.