For the last couple of years, I've used the Tag Suggest Thing WordPress plugin to recommend tags for my posts based on the post content. Beginning with WordPress 2.5, that plugin started to have problems interacting with the WordPress administration pages. In August 2009, Yahoo! announced that they would discontinue the Term Extraction service at the end of the month. Since the Tag Suggest Thing plugin relied on the Yahoo! Term Extraction service, it would become obsolete when the service was discontinued.
Yesterday, I posted a beta version of my Suggest Tags plugin to the WordPress Plugin Directory. This plugin behaves as a drop-in replacement for the Tag Suggest Thing plugin. It is updated to work with WordPress 2.8 and uses the tagging service from tagthe.net to generate a list of suggestions. Feel free to send me any feedback you think might be useful.