Wav=lossless.
AAC= extremely high quality lossless.
MP3=Standard, 128kbps is what soundcloud does but the max defaut bitrate for mp3 is 320.
Ogg= on par with aac.
WMV=AAC.
Also most audio sites do that for bandwidth reasons as most fellas are mobile.
Wavs are indeed lossless. They can still be of varying quality, it's just that the quality isn't further compromised by the format itself. 44kHz/16bit is the CD audio standard, and usually deemed "good enough" for most applications. There's also Aiff, which is Apple's version of the same thing, but it's becoming a bit of a rarity these days. Just so you know. But if in any doubt about quality, use wav - even in online streaming services it's usually better to upload .wav and let the platform handle the encoding to whatever format it uses.
AAC isn't lossless, it's lossy. It's usually achieves similar quality than mp3's at lower bitrates, which makes it at least more
efficient if not automatically better...OGG is similar in that sense. OGG tends to be kind of the Linux of audio formats, in the sense that while it's touted to being superior by a small-ish group of enthusiasts, it still lacks universal support, so it tends to be less useful than the ubiquitous mp3 (or AAC). AAC is afaik being used by Youtube these days.
MP3 is the lossy standard. A lot of streaming services still use the rather low bitrate of 128kbps, which can sound ok, but often fails/distorts in the high frequencies. Hihats/cymbals are usually the typical sounds that suffer from this. Higher bitrates can be pretty indistinguishable from CD audio, for example, at least in regular listening conditions.
WMV is, ahem, Windows Media
Video - the audio format is called WMA, unsurprisingly.