One of the most contentious changes in the webmail format has been the substitution of ME for the more informative 'Recipient" in the Sent folder. I did some searching on the Yahoo "uservoices" boards and discovered that, although numerous users have complained about this, Yahoo reps keep closing the complaints with a dysfunctional suggestion to disable conversations. Reps here favor reversion to Basic mode.
Both are poor workarounds because either way, the user must forfeit the benefit from conversations in other folders just to get a usable Sent folder. If the designers really think that conversations are good, why did they construct the webmail client so that users choose between using their Sent folders or conversations?
The Sent folder is not an inbox. Every other mail client ever developed recognizes this and includes the Recipient's name in all views of its contents. For some reason, the Yahoo developers refuse to acknowledge their mistake and keep acting as though users "just don't understand". In realitity, it's the Yahoo folks who don't understand. We need to keep posting/voiting on this issue until they do.