One thing I noticed is that searches no longer require that all words in the query be present in the search results. Adding a + before a word is now required to ensure that it's present in results. That frequently results in me having to do 2-3 searches to find something that could previously be found with one.
Another annoying snag is that if you search for "A B", google will also search for "AB" (eliminating the space). This affects a lot of searches with acronyms and technical terms. For example, if you're looking for info on MIT's RAs, the top search results for "ra mit" or "mit ra" are related to "ramit" or "mitra".
This seems to be an optimization for their average user, but is really inconvenient for people searching for system errors, mathematical/cs theory terms, or other queries where acronyms are common.
I have no idea why they changed this, I noticed it recently and I can't figure it why.
User testing must have somehow played a role, I hate to blame non-technical users but... still I can't believe anyone gets better results when the keywords are optional.
The odd thing is I remember switching from AltaVista to google, before google you always had to discount the first bunch of results, but google was just so amazingly accurate. And yet now I find myself skipping the top results in a google search.
I remember when google bombing first started, it didn't bother me much, but then google tried to counter it and I could swear searches got a bit worse. And recently they've gotten even worse.
It's a shame this seems to be destiny of all truly great things.
Even with the +, google makes some interesting "interpretations". I notice when I search on one of the BSDs (e.g. OpenBSD) it seems to pick pages that just have BSD on it.
Plus, google's handling of punctuation (e.g. f-script) is a pain since (even with the +) it will do weird substitutions and consider blanks good enough.
Since I started using more advanced search features regularly I have gotten significantly better results. Things like +"my search term", -free, -download, -cracked tend to heavily limit the spamming of results, and if I want something specific using tricks like inurl:keyword and site:siteToSearch tend to make what I want just jump out on the first page.
One thing I noticed is that searches no longer require that all words in the query be present in the search results. Adding a + before a word is now required to ensure that it's present in results. That frequently results in me having to do 2-3 searches to find something that could previously be found with one.