There is a fairly active English-language group devoted to recent books about Taiwan and by Taiwanese authors in the Facebook group Books about Taiwan: Discussions and Nerdiness.
The Association for Chinese and Comparative Literature has an English-language Facebook group that frequently has posts on Taiwanese books.
The Modernist Studies in Asia Facebook group sometimes has posts on related topics.
Other Facebook groups that may have some posts related to book history include the following:
The English and American Literature Association of Taiwan (EALA) has an associated Facebook group. Posts are usually in Chinese.
The EARN (Enlightenment and Romanticism Network) at National Chengchi University sometimes has posts about interesting lectures or other events.
The Taiwan Association of Classical, Medieval, and Renaissance Studies (TACMRS) has an associated Facebook group.
Taiwan Historical Review has a Facebook group.
The Taiwan Shakespeare Association has an associated Facebook group.
The Taiwan World History Group (Clio-Taiwan) has an associated Facebook Group.
Please contact me if you would like to recommend that I include any other useful social media groups.
Please also see the Scholarly Communities in Taiwan page.
Book History in Taiwan 