What's the buzz on the latest and most improved buzz monitoring sites? Here's a guide to seven of the best, along with some of their peers and competitors.

In March, I reviewed eight search sites spanning a range of specialized subjects, including local, social, and mobile. Since then, I've been keeping tabs on dozens of innovators, many of which will be featured in future roundups. This week, we'll review some of the most useful and interesting tools that you can search for brand monitoring, competitive intelligence, and campaign planning, to name just a few ways you can use them.

Facebook

Facebook Lexicon: Lexicon is simply Google Trends for Facebook. Enter up to five terms separated by commas and find out the relative frequency of how often those terms appear on Facebook Walls, the public message boards on users' profiles. It doesn't work perfectly; try a search on "clinton" and then "hillary clinton" and you'll see that the two-word phrase returns a lot of missing spots. Still, Lexicon marks a first step to gauge some of the buzz on Facebook. For example, it shows that Yahoo closely trails Google and they spike at similar times, but there's not a lot of love for Microsoft. What you can't do is gauge the context of those mentions.

Twitter

Summize: In a column about searching Twitter several weeks ago, I mentioned Tweet Scan. Summize is another Twitter search engine with more functionality. Neither engine catches every post; routinely some will only show up on one or the other, so if you don't want to miss anything, check both. I'm generally more impressed with Summize, and Summize Labs offers even more potential. You can also use the "near:" modifier to narrow results to people writing from a certain zip code, like in this example for a search on Starbucks. One advantage for Tweet Scan is that it works better on a mobile browser, which comes in handy when you're at events trying to search for fellow tweeters.

Flaptor is another Twitter search engine, and given how it's hard to find one perfectly comprehensive resource, it helps to have options. The best part is that you can easily graph each search term, or you can go directly to its Twist trend tool. You can compare about as many terms as you can think of, though as you can see in this example of comparing ten terms, after a handful it gets hard to read all the lines on the graph.

Keyword Demographics

Quantcast: This measurement service isn't new, and I'm not sure how long this feature's been around, but you can track the demographics of searchers for a particular keyword. It's not readily accessible as a search option, so the easiest way to do it is to visit this link for the demographics of "weather" searchers and then replace "weather" with your keyword of choice. You'll see the estimated monthly unique searchers, and then U.S. demographic information for gender, age, household income, ethnicity, head of household education, and children 6-17 in the household.

Message Boards

BoardTracker: Much of this social media craze isn't all that new; people have been posting on online message boards for decades. BoardTracker offers a new way to search all those posts across thousands of niche message boards you've probably never heard of. You can also set up email alerts and other ways to track posts. New features appear regularly.

Twing: Yes, there's even competition among new forum search engines, and while I haven't used either extensively, I'm partial to Twing for its design and how easy it is to refine searches. It also has similar features to BoardTracker for saving searches and alerts.

Blogs

Trendpedia: Hardly the first blog search engine (see Technorati) or even the first one with comparative charts for blog buzz (see BlogPulse and IceRocket), it's the newest entry, and one that's been making rapid improvements. One convenient feature is that when you enter two or three terms to compare, it instantly shows a pie chart with the percentage of blog posts mentioning each term. Additionally, clicking anywhere on the graph opens up a new tab on the screen to see posts by date.

It's hard to say if any of those sites are better than the other, though BlogPulse has been the most neglected recently. There's still an opportunity for others to establish themselves with more intelligent tools, such as accurately gauging sentiment and noting how influential the blogs are that are doing the buzzing. Technorati has offered a filter of blogs by authority level, and Summize Labs offers Twitter sentiment analysis, but these just scratch the surface.