Do sitemaps actually accomplish anything?

Are they helping anyone to "push" new pages into the index?

[anax]

I have an informational site that's been well indexed by Google for a long time - no problems in that regard.

I recently created a "news" section within the site, and from Google's descriptions of Google Sitemaps it seemed like it would be good to use a sitemap for this news section, because new pages appear in it frequently, sometimes more than once a day.

In the past, I've never had trouble getting new pages into Google: somtimes it takes a week, sometimes they miraculously appear the next day -- just random fluctuations. Now with my new news section I was hoping that a sitemap would let me guarantee that the new pages get indexed within a day. (I'm not talking about *ranking* - if the new page is 1st or 100th it doesn't matter; I'm just talking about getting into the index.)

Having used Sitemaps for a few weeks, as far as I can tell it doesn't do a thing. Occasionally a page will get in the next day, while other times they don't appear for a week.

I edit the sitemap myself and upload it by hand, and do it just for this one section of the site. But I can't see that it does a thing. So is there any point in wasting time to do this? Are sitemaps actually helping anyone get new pages into the index more promptly? I'm beginning to wonder if Google isn't rushing a lot of new services out the door before they actually do anything useful.