There is! I'm not technical so I can't give details, but LiveJournal has an API for posting and Dreamwidth inherited it. I don't know if they've modified it (in support of the new features), but I know people have used LiveJournal clients to post here just by repointing them. (Given the differences in access/filter lists, I have no idea whether that's still possible or if you'd need a Dreamwidth client.)

Searching the FAQ I find a brief mention of clients you can use - which links to a wiki page that lists clients and also gives (some) details of where the API url's are.

You may (or may not) also be interested in the guide The ethos and ideas behind Dreamwidth Studios: What makes us special? Some of it is, as I noted, a culture thing for some people.