I make status updates to this page frequently, which goes on the wall of 3000 people, and that is good.
I just recently put a facebook like button (fbml, with an app id) on a page of my website and now it has 300 likes of its own:
Facebook makes a sort of virtual "page" for this page on my site. And I can make status updates to these "like-ers" via that virtual page.
So...In future, in order to get status updates to both sets of facebook "like-ers" it looks like I will have to post to both places. If I put like buttons on 10 pages of my website, I'd have to post my status updates to 10 places. This seems like a bad idea.
Is there a way that I can make a facebook status update in one place and have it go to all these different pages? Or is it better to just have all likes point to facebook.com/mydomain?
It depends. Is this a biz or personal? What is your goal? The folks here are not too keen on FB because you're restricted to what you can and cannot do on the web. FB keeps changing the rules and people's attitude toward FB is evolving. And as that changes, the attitude toward your page on the web could change for the worse.
It's better to have all of your likes going to your own web page.
There are services that allow you to link into Facebook and your website. Some email marketing packages, for example, allow you to Twitter, update your website and your FB page when you send an email out. Also, take a look at an outfit called Involver who has FB apps.