A Google Web Search Help thread has complaints from searchers that Google is showing the "see more results from..." feature a lot less often.
It appears that it is now only showing for navigational queries only, such as [search engine roundtable] but not for long tail queries such as [google sitelinks forums].
Here is what works currently:
But if you search for something less navigational, you don't get it:
You once did, as we have a picture of this exact query from 2009:
This is a feature that went live as far back as 2005 and now Google seems to be limiting it.
Google's Jessica responded in the Google Web Search Help saying this is still working but showed a navigation query. She wrote:
Could you please provide examples for which you currently don't see that this it and know that you had previously seen that it was working? I'm seeing that it's working for an example like EPSN.go.com (see screenshot below).
Forum discussion at Google Web Search Help.
Update: Google's Jessica confirmed it has been removed in these cases. She wrote:
It sounds like the examples everyone has given are about discussions. "More results from" forums is unfortunately no longer available. I'm sorry to hear the change is disappointing and frustrating to those who posted here about it.