How to

Spot HOTPopular Trends

Search

Google Hottrends- most popular searches. Updated hourly.

Bing xRank - top searches on Bing. Updated daily.

Aol HotSearches - top AOL searches. Updated daily.

Yahoo buzz  - buzz score is the percentage of Yahoo! users searching for that subject on a given day, multiplied by a constant to make the number easier to read. Weekly leaders are the subjects with the greatest average buzz score for a given week

Top AskIQ - most searched at Ask.com for the previous week

SEOmoz PopularSearches - aggregates search data from most sources listed above.

Social Media

Delicious - most popular tags and bookmarks

Flickr tags - most popular tags for the last 24 hours, over last week and overall

StumbleUpon - most recent hot tags and most popular all time tags

Twitscoop - most popular terms on Twitter for the day, week and month
 

Blogs

Twittorati - top tags on Technorati and Twitter

BlogPulse - top phrases and blogbites from the previous day

Technorati Popular - popular searches and top 100 blogs

eCommerce

Amazon - most popular tags cloud used by Amazon customers

EBay pulse - most popular eBay searches