Sample code for 30+ languages & platforms
PowerShell

Yahoo! IMAP (imap.mail.yahoo.com)

(from Wikipedia)
It is possible to get direct IMAP access without signing up for paid access nor using software like YPOPs! or FreePOPs. Yahoo! operates IMAP and secure IMAP servers (imap.mail.yahoo.com in particular), which are globally accessible. However they require a specific, non-standard IMAP command to be sent before login is done, namely: “ID ("GUID" "1")”.
This example demonstrates sending the non-standard IMAP command after connecting but before login.

Chilkat PowerShell Downloads

PowerShell
Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

$imap = New-Object Chilkat.Imap

# Connect to they Yahoo! IMAP server.
$imap.Port = 993
$imap.Ssl = $true
$success = $imap.Connect("imap.mail.yahoo.com")
if ($success -ne $true) {
    $($imap.LastErrorText)
    exit
}

# Send the non-standard ID command...

$rawResponse = $imap.SendRawCommand("ID (`"GUID`" `"1`")")
if ($imap.LastMethodSuccess -ne $true) {
    $($imap.LastErrorText)
    exit
}

# Login
$success = $imap.Login("myLogin","myPassword")
if ($success -ne $true) {
    $($imap.LastErrorText)
    exit
}

$("Login Success!")

# Select an IMAP mailbox
$success = $imap.SelectMailbox("Inbox")
if ($success -ne $true) {
    $($imap.LastErrorText)
    exit
}

# Continue with whatever you wish to do...
# (see other examples..)

# Disconnect from the IMAP server.
$success = $imap.Disconnect()