Latest version: 1.9.8
Try the Text2Link Firefox+Thunderbird extension for yourself. You’ll wonder how you browsed without it.
To download and install Text2Link for Firefox, visit Mozilla’s Text2Link for Firefox page and click on the Add to Firefox button.
To download and install Text2Link for Thunderbird, visit Mozilla’s Text2Link for Thunderbird page and follow the three steps in How to Install in Thunderbird.