Re: Please help a penguin
Telnet is quite OK in a closed network where you have no need to secure communications.
Or if you secure it. Telnet over TLS, Telnet with STARTTLS, Telnet with Kerberos authentication, Telnet with SRP, Telnet over point-to-point VPN...
Hell, you can run Telnet over an SSH tunnel, which is damned useful if you need any of the Telnet features that SSH doesn't provide, such as TN3270.
Certainly there are infelicities with the Telnet protocol. It's a right pain to implement (I've done two Telnet server implementations), with its rather ornate negotiation process and in-band signalling. But it's very flexible and capable of many things that aren't part of SSH (and while they can be bolted on by adding another protocol layer, there's no standard for them).
And, of course, as boltar (I think) mentioned, using the telnet client as a quick-and-dirty TCP bytestream client for development and testing purposes is a time-honored tradition. Sure, you can do the same with eg netcat, but telnet is widely available.
(The willingness of Reg commentators to boldly display their ignorance in threads like this would be impressive, if it weren't so common everywhere online.)