I did a search on the words "htc sense" and only one article came up. I started entering a question with the words HTC and sense in the title and several article were suggested with both words in the title. Is there a problem with search?
As I noted in a comment, we do auto-convert search terms that match popular tags, into tags, if they are in the top (n) tags on a site.
This doesn't work so well for small sites though!
I added another sanity check so that we only do this auto-mapping when the # of questions in the tag is 200 or more.
So, this shouldn't be happening now.
It appears that the default search treats terms as tags. "htc" would only find the htc tag. "sense" would only find the sense tag. htc-sense would be required to find htc-sense tag.
intitle:2 htc sense
Would be required to search for titles with "htc" and "sense".
hmm, looks like the search doesn't pick up on the htc-sense tags, or the htc OR sense tags. This would be a question for Jeff, you may want to cross post it to meta.stackoverflow.com
Definitely something funny with search, I see no results searching for "google earth"
Even though there's a question with those words in that order in the title, a tag called google-earth, and I can remember seeing another couple of questions lately that reference Google Earth in the main question text.