The web isn't color managed or not, it's the browser that counts (they either are and any tagged RGB document will preview correctly or they are not). Many web browsers will handle Adobe RGB (1998) just fine, some will not. And sRGB is the same; uploading sRGB doesn't guarantee a match without a color managed browser.
See:
sRGB urban legend & myths Part 2
In this 17 minute video, I'll discuss some more sRGB misinformation and cover:
When to use sRGB and what to expect on the web and mobile devices
How sRGB doesn't insure a visual match without color management, how to check The downsides of an all sRGB workflow
sRGB's color gamut vs. "professional" output devices
The future of sRGB and wide gamut display technology
Photo print labs that demand sRGB for output
High resolution:
http://digitaldog.net/files/sRGBMythsPart2.mp4Low resolution on YouTube:
https://www.youtube.com/watch?v=WyvVUL1gWVs