Others complain it finds things that aren't actually viruses or malware,
but it's probably far more common for the program to find actual problems but give a meaningless identifier that just confuses people (and that has no reference on the web).
@1)
"Malware" is a wide field which doesn't comprise only "viruses", trojans or worms, but also Adware, dialers, "spyware", PMS/PMA/unwanted tools etc ect pp
if it's not malware what avast finds, then it's a false positive
@2) Well of course it has a reference on the web (see above)
except if it's brand-new or not itw/wide-spread
true, avast's own virus-list on its HP is not the most detailed, and Detections like "Trojan-gen" or "Trojano-xxx" aren't exactly helpful for the layman, but would e.g. "Win32.Small.gl" with no further descriptive link help you better (see vgrep) ?
it's just not possible to have detailed info for every possible minor malware for avast (or they'd have to stop writing malware-detection-signatures and just write malware-descriptions in the future)