Blogger (as the Blogger help on blog ID is just slightly out of date).
Knowing your blog ID is useful for all sorts of things like tweaking autodiscovery for your blog's feed, adding trackback to Blogger and figuring out trackbacked posts, flagging spam blogs, displaying backlinks, link tracker, Cosmos etc for your posts, and other stuff I'll come to in future.
There are 2 alternative ways to work out your blog ID. Either of them is fine:
1. View source
- Go visit your blog in your browser.
- View source (Internet Explorer & Opera: menu View, Source; Firefox: menu View, Page Source)
- Search in the source window for "blogID=" (without quotes).
- The number after that "blogID=" is your blogID. E.g. this blog's ID is 8849059.
2. From your Blogger Dashboard
- Login to Blogger.
- You can't click on the name of a blog anymore, but find the name of the blog whose ID you want, in your Dashboard list.
- Current look Blogger: hover over any link in the bottom line for the blog you're interested in (outlined in red below, i.e. any link for that blog except View Blog); you can see the link's URL or web address in the browser status bar, or rightclick the link to copy it then paste it somewhere, or even click one of those links and check what it says in the address bar of the resulting tab/window. The blog ID is the bit of the URL that's after "blogID=".
- New look Blogger if you login via Blogger in Draft (still in Draft): again check out any link in the bit I've outlined in red (i.e. any link except View Blog) to find your blog ID number at the end of the link URL.