Salvete! Is it possible to add a webpart to a Wiki Home Page via Powershell? I have 100 sites for which I need to add a web-part to their home-pages. I know this is easily possible with normal web-part pages, but how about a wiki-home page?
Yes, it's possible. I had a blog post on this very topic, but the blog site has since been deactivated. Basically you do it like you would add a web part to any other Web Part Page. When it's time to specify the zone, use the "wpz" zone. Also, you need to add some markup to the Page's "WikiField" that resembles this (substituting your Web Part ID Guid where appropriate):
This posting was similar to the content I presented in my (now deleted) posting: http://blog.mastykarz.nl/inconvenient-provisioning-web-parts-wiki-pages-sandboxed-solutions/