You can find out how often you (or anybody you know the twitter name of) is tweeting using TweetStats.
Use WeFollow to see who people with similar interests are following. It uses hashtags to categorize people by industry or hobby.
Xefer graphs Tweets and replies using Yahoo Pipes and Google Charts to display hour-by-hour information. The other cool thing about Twitter Charts is that it will show you all the @replies a person has ever used, sorted by person. You can quickly find out who they favor.
This is Twitter’s search page. Use it to search for keywords. There is also an advanced search option
Searches beyond Twitter’s history so you can search tweets further back than 10 days, in only friends’ tweets, within direct messages and within any user’s favourites. Really useful when you remember a tweet but forgot to favourite it and want to read it again.
Allows comparative searches of terms within Twitter. It is great for contextual analysis since the visual data (that can span from 24 hours to 30 days) is supported by the inclusion of qualitative data (the tweets that were used to generate the visuals). It is also a great tool for analyzing words in context as well as observing emergence of trends and patterns of communication.
A search engine for Twitter lists, which is helpful for finding users with interests similar to yours.
This searches for images in Twitter. It relies on user descriptions so can be a bit hit and miss.
Influence and Reach
Provides a comprehensive set of metrics about a search term or user impact on Twitter and complements the quantitative data with excerpts of qualitative inputs. An explanation of how the scores are calculated is available here. Calculating reach is useful when aiming to assess the number of exposures a message/account could gain as facilitated by its network.
Klout scores range from 0-100 and measure the overall online influence of a Twitter account. The score is “a factor of over 35 variables broken into three categories: True Reach, Amplification Score and Network Score” where “True Reach is the size of the account’s engaged audience and is based on the followers and friends who actively listen and react to your messages. Amplification Score is the likelihood that an account’s messages will generate actions (retweets, @messages, likes and comments) and is on a scale of 1 to 100. Network score indicates how influential an account’s engaged audience is, also on a scale of 1 to 100. The Klout score is highly correlated to clicks, comments and retweets.”
Aggregates social media stats from Facebook, Twitter, YouTube, Google Analytics, Myspace and bit.ly. Once authorized it collects and produces visualizations based on activity metrics: followers, lists, mentions, RTs, favorites, links and more. It interprets data into categories: reputation (followers and lists), influence (mentions, RTs), conversation indicators (Tweets, RTs, @replies).
Archives twitter data and provides some visual interpretation by default. This makes the analysis process even easier than with TwapperKeeper . It has options for viewing and downloading the data. The Archivist has also a desktop application which would enable working with other datasets as well.
Other ways of archiving Twitter include back-up options reviewed by ReadWriteWeb. Of some relevance might beTwistory and TwInbox, both downloading data to calendars and Outlook Express respectively.