There are two major versions of VRML: VRML 1.0 and VRML 2.0 aka VRML97 (this document does not discuss X3D, which can be considered version 3+ of VRML)
Flashpoint currently includes 3 VRML plugins. Live3D supports VRML 1.0. CosmoPlayer and Blaxxun Contact support VRML 2.0.
VRML files are plain text or gzipped plain text. If you try to open a VRML file and it looks like gibberish, try using 7-zip to treat it like it's an archive.
To tell if a VRML file is 1.0 or 2.0, it's sufficient to look at the first line of the file.
A VRML 1.0 file's first line looks like this:
#VRML V1.0 ascii
A VRML 2.0 file's first line looks like this:
#VRML V2.0 utf8
Different VRML files may behave differently in different VRML viewers. If the site that the file is on suggests a viewer and Flashpoint supports it, use that viewer. Otherwise:
Use Live3D for all VRML 1.0 content.
Use Blaxxun Contact for VRML 2.0 content that comes from multiuser Blaxxun-based communities (such as Cybertown).
For all other VRML 2.0 content, check to see if it seems to work better in Cosmoplayer or Blaxxun Contact. If it works well in both, use Comsoplayer(?).