Face-to-face:
Advantages:
Convenience/Fast
Good feedback
Can use body-language and word-emphasis to be more clear
Easy to stay on track
Disadvantages:
No recordings.
Only one speaker (usually)
A small number of listeners, possibly just one
Challenges:
Getting the message to a lot of receivers.
Harder to Lie
Relies on memory to retain information.

Group discussion
Advantages:
Larger pool of knowledge
Better Insight/More 'eyes' to see flaws
Easier to spread/delegate work
Disadvantages:
'Bureaucratic Inefficiency'
Easy to get off track
Shallow, not much time per person
Challenges:
Collective agreement
Controlling who speaks when.
Keeping a record.

Presentations/speeches
Advantages:
One talker, no interruptions
Easy to 'export' information
Good for educational purposes
Larger audience
Good for experts giving their views
Can use power point and such
Disadvantages:
Little to no feedback
Difficult to hand over anything to listeners
Easy for the audience to misunderstand
Challenges:
A lot of pressure on one talker
Keeping the audience's attention/interest
Being heard
Negative feedback

Letters
Advantages:
Easy to backtrack/store/refer to
Allows for multiple 'drafts'
More personal/physical
It doesn't get lost in 'Junk mail'
Disadvantages:
Limited by physical size
Time consuming
High cost, probably highest.
Slow/Late feedback
Challenges:
Need to be physically delivered
Easily lost
Being readable/Can require good handwriting

Reports
Advantages:
Specific Information (topic)
More in depth information
Predictable formatting
Disadvantages:
Very time consuming
No direct feedback
Excess Information
Can be interpreted differently
Challenges:
Deadlines
Formal Standards
Needs to be the right information

E-Mail
Advantages:
Stored
Can be sent to multiple receivers at once
Multiple drafts
Easily searched/backtracked through
Disadvantages:
Can be lost
Can be hacked/exposed
Impersonal
Up to interpretation/No immediate feedback
Potential virus vector
Not everyone checks it frequently
Requires the receiver to be online.
Challenges:
Having the e-mails oriented
More competition for the receiver's attention
Sending to the right address

Instant messaging.
Advantages:
Easy to delegate tasks
Large numbers of people can talk at once
Stored, at least short term.
Disadvantages:
Limited medium/features
Requires the receiver to be online.
Can lie about their identity
Challenges:
Potential information overload
Keeping the conversation on point
Agreeing on a channel/platform.
Kappa