It’s okay to link external sources as long as you describe them shortly and highlight openHAB specific aspects. What you shouldn’t do is “spam” the forum with external links. 
Regarding Tasmota, we have an article on that as well: ITEAD Sonoff switches and sockets - cheap ESP8266 Wifi+MQTT hardware
Btw. The article as well as a big part of the Tasmota wiki content is written by me 