A web browser is at its core a simple thing, a few lines of PERL and you can write a very basic one. What is important about a browser is its elegance and simplicity and its reliance on simple standards like HTML or server logs etc.
Weblog tools can be simple and elegant and they too rely on simple standards however they are not formalized and this is getting scary. At first glance I can think of four key pseudo-standards for the writeable web. Getting these right will surely have huge implications if weblogging is anything like as important as web browsing:
1. The Meta Weblog API – needs to be modular.
2. Pings from posts (make weblogs.com the principal server and post the whole message)
3. RSS – freeze on 2.0 with slightly tweaked core and generic XSLT to create RDF if needed.
4. Permalinks (oh yes) – standardize formats and ability to alias through purl.org etc.