I've been working mostly on graphics formats. I expect that it will stay that way, though I'll do occasional work on other topics.
I'm going slowly, and trying to verify the information I post. I'm not sure that's such a good thing, though – at this stage, this project might be better served by focusing on quantity.
What I hope to contribute is concise practical overviews of formats, and links to useful or historically significant resources.
Disclosure: I'm the author of Deark, a work-in-progress utility that converts or extracts miscellaneous things from miscellaneous formats. (OK, actually, it mostly just decodes image files.) I intend to list it as a resource in articles where I humbly believe it could be useful.