If someone tweets about you on Twitter and you don't hear the sound, did the tweeter tweet at all?

This is one of the philosophical questions about Twitter that has a practical answer. Fortunately, now there are many ways to listen to the tweets.

I last covered Twitter six months ago, focusing on how to use it for buzz monitoring. At the time, there weren't many options for searching Twitter, though by then Twitter came out with its tracking tool for IM and mobile. Today, Twitter still offers little search functionality, but other options have emerged.

Why care about Twitter? It's a playground for early adopters, and for many technology enthusiasts, Twitter's the best way to reach them. Google Trends shows Twitter buzz is at an all-time high in search volume right now, and it's not that far behind search volume for the movie "Iron Man"(though compared to Facebook and MySpace, they're barely a blip). Twitter is a communications channel for messages that are too brief and perhaps fleeting to blog, but for whatever reason, they matter enough for someone to write them. The more people tweet on Twitter, the more search matters to find out what they're saying.

Here are a few ways to go about it:

Tweet Scan: Tweet Scan is what you'd expect from Twitter if it had a real search engine (you can only search for users on Twitter.com). At Tweet Scan, you search the content. If you're doing some brainstorming for how to promote a new kind of coffee and want to see what people are tweeting about, entering "coffee" on Tweet Scan will bring up countless posts. People happen to like mentioning they're drinking coffee, whether it's noting they're taking a coffee break, they're going to their local coffee shop, or they're trying to stay awake. Coffee is one of those perfect Twitter search terms, as it's something people engage with a lot but generally never wrote about publicly until this communications channel came along.

While Tweet Scan's useful, its limitations are too numerous to list. You can only go back 10 pages of Tweets, which may or may not be a lot depending on how hot the subject is. There aren't any graphs, and all analysis is manual. But it does cast a wide net, so if someone's talking about your query, Tweet Scan will find it.

Twhirl: Once you're ready to do more than a periodic search and you're at least dabbling with using Twitter to communicate, then it may be time to download Twhirl, a desktop client built on Adobe AIR. While Twhirl can be a little slow at times for those who need up-to-the-minute information, it incorporates Tweet Scan's search functionality so you don't need to keep going to the Web for it. There's also an option to use Terraminds Twitter search, but that hasn't worked in months. The main benefit for Twhirl is that if you're talking as well as listening, Twhirl lets you do it all in one place.

FriendFeed: If Twitter's too mainstream for you, you can find a subset of tweets using FriendFeed, an identity aggregator that lets you publish updates from a range of social media sites including Twitter, Flickr, del.icio.us, digg, StumbleUpon, your blog, and dozens of other sources. Then you can befriend others and follow all their feeds. It's similar to Plaxo Pulse, but at Plaxo, you need to log in to search, and you can only search your friends' posts. You don't even have to be registered with FriendFeed to search it; just click the "everyone" tab on the homepage and enter a search. While the majority of results in FriendFeed tend to come from Twitter for any query, the other social media listings provide a broader perspective of what's being said and shared.

Quotably: If you're looking to follow conversations and not just posts, turn to Quotably, which semi-reliably groups conversations together. On Twitter, people direct public responses to each other by writing "@username" and the message, replacing "username" with a person's Twitter name. Those messages are public, so if the recipient is closely monitoring Twitter, he or she will find it. Quotably compiles those threads. To see it in action, enter a username such as comcastcares or hrblock, as such marketers are actively engaging in conversations. You can also run a search on any keyword, but you're more likely to find a series of one-off posts rather than discussion threads.

With these tools, it's now possible to monitor the conversations. That's the first step before deciding whether to join them.