hello hotdog,
By definition a wiki is: a collaborative Web site set up to allow user editing and adding of content usually without restriction. Wiki's are basically collaborative community efforts that anyone with a web browser can modify, or add to already existing content. The most popular version of a wiki on the internet today in my opinion is
www.wikipedia.com . Wiki's are good for posting things like historical facts like what you do in your blog, and i think that you can request to have exclusive writing access to your wiki through the MyPTSMail service so that no one else can modify your entries. Wiki's nowadays have themes too similar to the blogs but i think they are much less graphical. I think the blog themes are better but that's probably because i prefer attractive websites that are informative over just informative ones.
By definition a web log is: an online diary; a personal chronological log of thoughts published on a Web page. Basically it's typically the thoughts, interests, or practices of a single author put on a web page for everyone to see. Web surfers cannot edit the content, they can just comment on it.
I think you could successfully do a wiki or a blog with your history ideas because both blogs and wikis are very search engine friendly. Blogs have plugins and other features that push their content out to the search engines fast, and so do wikis. I think both have equal potential to large audiences, but i think the big difference between the two is how you go about searching for the content in them. I think blogs are for the most part easy to navigate, but sometimes its easier to find what your looking for in a wiki. In the end i think it's just a matter of preference. goodluck!