Simsi - 12:30 pm on Sep 3, 2012 (gmt 0)
We have seen our most generic search term rise from 3rd to 1st over the weekend and traffic for that keyword rocketed, yet long tail has become almost non-existent for most of last week and the weekend.
I've seen exactly the same on more than one focused niche site I manage over the past 3 months. My best guess to now is that Google can't see a relationship between the longtail terms and the key term.
To a degree I can understand that. For example if you are writing about Beautful Objects and one page is about diamonds and one is about a rainbow, there is no obvious correlation and I can't see how Google could possibly understand ther eis one - unless you for the search engines, which we are discouraged from doing.
The answer is more work, clutters up the web with small sites and leaves you feeling annoyed lol, but seems to work: a seperate site for each beautiful object. One index page of useful content and a couple of pages of related fluff around the subject to boost internal links back to the main page seems to do wonders.