My atom feed is atom.xml, and yet recently Blogger has been breaking that. Only yesterday, it was wrapping everything in an <html> block (which meant that no feed parsers could use it). Fortunately, I'm glad to say that that problem appears to be fixed, but it's a bit of an emabarrassment when you can't even get a feed format right that you've been pushing for.
It's still serving the content up incorrectly though:
$ wget --server /atom.xml Resolving alblue.bandlem.com... done. HTTP request sent, awaiting response... 1 HTTP/1.0 200 OK 2 Content-Type: text/html; charset=UTF-8 3 ...
So it's not being served correctly as application/atom+xml. Worse, it's not even being served as an XML type.
Lastly, even though all of the posts that I write are valid XHTML, the content that's being served out in the feed is now being sent out as HTML instead, which means that > and < are being written out as < and > each time. Admittedly, this is better than RSS, in which it's a bit of a random guess as to whether the content is encoded in this way; at least the atom feed (correctly) tells the parsers which is which. But you used to be able to include a CSS stylesheet that would let you view a feed in an HTML browser, by virtue of styling individual elements; now, you can't do that (and blogger don't add that stylesheet to the feed any more). It's not a big deal, and it's still within the Atom spec, but if you've already got a bunch of valid XML what's the point?
Oh, a quick note about advertising and spam; I do delete both spam and advertising comments on my blog, so don't bother leaving spamvertising here. Frankly, I don't know why Blogger doesn't have a 'report spam' button against comments (in much the same way that you can delete comments) and let them build up a network about what a spam comment looks like. After all, that's how they train GMail; why not do the same for blogger comments too? I bet that highly prolific spammer 'Anonymous' wouldn't be back ...