spam-preventiontwitter
Are there any applications that can help determine the "spaminess" of a Twitter follower?
For example, looking at whether the user unfollows people who don't follow back, whether most of their Tweets are promoting a single site, or whether they follow indiscriminately.
Twitter client that connects you with other Twitter users in your local city or town.
In the picture below you can see it is paired with Google Maps.
These tweets are always public. Anyone can see them anytime. But Twitter website is not built to show @B's replies to @A on the home timeline if they are not following @A. But there are Twitter clients that does it. I remember TweetDeck having this feature. It'd show the followers of @B all of his tweets and replies to @A even if they are not following @A.
Best Answer
Besides the disproportionate ratio of followers to followings already mentioned, I've seen spammy followers show up because their area of work (?) is related to a keyword of my last tweet. I don't tweet often, and I don't have lots of followers, so this is pretty easy to spot manually.
My conjecture is that some spammers search tweets containing particular keywords, and then follow those tweeters, perhaps hoping to get a follow back and a voluntary reader of their spams.
When you get a new follower, cross reference the content of your last tweets and the keywords of their interests (if they're commercial). You'll detect the spammy followers.