Types of Norse Paganism
To elaborate on the information given on the what is Heathenry page, I will go into more detail about the different "flavors" of Norse paganism that are out there. It is not necessary to pick one of these, there are many people who begin and end their description at "Norse pagan", but these terms show up a lot and are worth exploring.
Asatru literally means "faith/belief in the Æsir". Asatru is the most common form of Norse paganism (and Heathenry in general) and tends to have a heavier focus on the Aesir group of deities (but typically not an exclusive focus on them). Asatru (along with Vanatru and Rokkatru) came about sometime in the 1960s and 1970s, with the formation of Ásatrúarfélagið in Iceland. As far as I can tell, Heathenry was already popping up in places (including the US, UK and Canada) independently of the Asatruarfelagith, but they seem to have been the ones to popularize the term "Asatru".
Vanatru has similar roots to Asatru, though with more of a focus on the Vanir family of deities. From The Way of Fire and Ice, "Vanatru developed in response to the Aesir-centric practices of Asatru by people who felt the Vanir were not honored enough and were more called to that tribe."
Rokkatru is the more recent of the main three offshoots of Norse paganism. Rokkatruar focus their attention more on the jötnar (joetnar from this point forward), the giants from Norse mythology.
Forn Sed (or Forn Sidr), meaning "the Old Way", is a common form of Norse paganism practiced primarily in Northern Europe and Scandinavia. Forn Sed practitioners base much of what they do on oral tradition and folklore.
Odinism is a Neo-Volkisch form of Norse paganism. They are fascists. Groups to avoid will be listed here.