a chrome extension
Because sometimes 140 characters is not enough
What this Chrome extension does
The Chrome extension alters your Twitter settings on the front end to enable posts in excess of 140 characters. It doesn't update the counter, but you can now post anything up to 280 characters.
27/09/2017 - 2249UTC
I believe Twitter have patched this server side, as such the plugin will no longer work. There is plugin here may still work in Tweetdeck until patched.
This plugin is not endorsed by Twitter.
Built by @td_evans