There is different reasons to want a personal wiki on your machine:

-  privacy
-  having it everywhere

I've tested a few wikis engines, like
[[http://tiddlywiki.com/][tiddlywiki]], but I've found nothing that was
really what I wanted. The main inconveniance is the need to use a
webbrowser. A browser is not a text processor, so it's really painfull
to use them for writing.

I've started to try to use vim as wiki. Why would I want to use
something like vim for this ? well, it's plain text (easy to grep, or to
write script for manipulating data), application independent, it's a
real text processor, you can customize it, and most importantly, I know
how to use it, ...

I've got a *wiki* directory in my home directory, with all my files in
it. I use git to track versions of it (you can use svn if you prefer,
there is no difference for this usage). In my .vimrc, i've added this
instruction: =set exrc=.

In my wiki directory, i've got another .vimrc with some specific
mapping:

#+BEGIN_EXAMPLE
    map ,I  <esc>:e index.mkd <cr>
    map ,T  <esc>:e todo.mkd <cr>
    map ,S  <esc>:e someday.mkd <cr>
    map ,c  <esc>:s/^ /c/<cr>
    map ,w  <esc>:s/^ /w/<cr>
    map ,x  <esc>:s/^ /x/<cr>
    map gf :e <cfile>.mkd<cr> " open page
    map <backspace> :bp<cr>
    imap \date <c-R>=strftime("%Y-%m-%d")<cr>
    set tabstop=2                   " Number of spaces <tab> counts for.
    set shiftwidth=2                " Unify
    set softtabstop=2               " Unify
#+END_EXAMPLE

I organize my files in directory. I've got a *work*, *lists*, *recipes*,
*misc*, ... and I put my files in this directory.

I've got an index page, with links to main section. I don't have
wikiword in camelcase or things like that, so if i want to put a link to
a page, I just wrote the link this way *dir\_name/page\_name*, then, i
juste have to hit =gf= on this link to open the page. I also use this
place as a todo list manager. I've got one paragrah per day, like this :

#+BEGIN_EXAMPLE
    2008-06-14
        - [@context] task 1
        - [@context] task 2
        ...
#+END_EXAMPLE

and a bunch of vim mapping for marking complete (=,c=), work in progress
(=,w=) or canceled (=,x=).

If i don't have a deadline for a particular task, I use a 'someday'
file, where the task is put with a context.

The good things with markdown, is that the syntax is easy to use, and
it's easy to convert to HTML.