This week, I'm seeing spambot accounts with reasonable following ratios, believable names, and bits of text that would almost make sense as entire thoughts or sentences, if you didn't understand that a word like "uni" for "school" or "college" wouldn't be used by a girl in Louisiana, particularly not in the middle of August.
Big giveaway: name reads "Kayla," Ms. 'Claire.' Ooops!
The linkspam volume has died down. You could almost believe it's a real account, not just a broadcast mouthpiece for porn, SEO and MLM links.
One giveaway the nasty spammers seem to fail to be dealing with: the source parameter. Without an officially registered app, the source parameter describing the app that a tweet was sent from is going to be displayed as "From API." Not "From Web." Not "From Tweetdeck" or "From Seesmic" -- "From API."
With OAuth, there's no reason for legitimate users to be calling in over Basic Auth anymore -- no reason a legit user should be displaying "From API" -- certainly not with any regularity.
Developers: register your app, use the freely available OAuth libraries that are proliferating, and deal with the occasional OAuth downtime.