FWIW, complaining to Twitter support has had zero effect and there are just too darn many of these automated bots to report every one as a spammer. I did try a couple days ago and reported about 100 of 'em to no avail.
Most avid tweeps use some sorta third-party client to manage their tweetin' -- like TweetDeck or Hootsuite. I typically use Hootsuite and have a column dedicated to the Canadian politics hashtag, #cdnpoli. When the spambots run rampant, my #cdnpoli column looks like this:
TweetDeck ain't any better:
Now, my workaround ain't ideal but it at least makes it possible to indulge my addiction to #cdnpoli. During the bot blitz, I go back to basics and use Twitter without any third-party thing. I have a saved search for #cdnpoli and by selecting "Top" as the filter, I get a feed that looks like this:
No bots at the top of the list. As I said, it ain't perfect but it at least makes #cdnpoli somewhat usable.
The bot blitzes usually last for a couple hours. After the blitz, I revert back to Hootsuite.
If anyone has any other ways they're dealing with the onslaught, please tell about it in the comments here.