[miki123211]

Will this be a lock in feature that makes it harder for people using external mail clients?

[brajesh]

Won't it simply fallback to regular email view on external clients, like outlook's "recall email" function?

[alkonaut]

The reasonable implementation would be to not send anything more than a link to a site where the receiver can view the content.

[X-Istence]

Which is exactly what this does... and now I can't search my email for relevant information anymore.

This is a step back.