In essence the Skype product feature set has never differed much
from instant messaging and open source competitors. At least when
viewed as a simple feature 'tick list'. What Skype has done uniquely
well, though, is to tailor every part of the product experience for
ease of adoption: from investigation to use to recommendation onwards.
This could glibly be dismissed as 'viral marketing', but that
doesn't do justice to the depth of their achievement. For the term
'viral marketing' doesn't explain how everything in the web site and
product is oriented towards getting people on board with the minimum of
obstruction. The term 'viral marketing' merely focuses on the moment of
contagation.
To find out how well Skype's doing, you just need to take a look at
some of the competition. Let's examine the download experience of AOL Instant Messenger, MSN Messenger and Yahoo! Messenger, and contrast them to that of Skype.
(Apologies in advance for the layout mess of this article; I just don't have the energy to do some fancy CSS to put borders around the images and scale them better.)
AOL Instant Messenger (AIM)
First up to the plate is AOL. "Mum, just go to the AOL home page and grab their messenger client, then we can chat for free." Oh, yeah.
AOL, MSN and Yahoo all have a problem from
the word 'go'. An a non-US resident, which web site do I go to? The
".com" or the ".co.uk" one? (Skype is notoriously global in outlook.)
Let's assume we go the .com route every time. After all, my IP address
is trackable to be in the UK, my browser is telling them my preferred language is "en-GB". They've got enough clues.
So let's hunt for the entrance to the rabbit hole:

OK, it's there. It has a nice biggish
icon. It just requires you to be telepathic and know that "AIM" is
their codeword for their instant messenger. And that "Join AOL" isn't the same thing as, um, joining AOL's IM network. Let's click forth…

Good - a call to action, bang in the middle. But there are some
niggling 'buts'. What if I get distracted by their kind offer of a
trial of their new client? I'm outside the US (see bottom of
screenshot) — do I need to download something different? I don't have a
screen name — am I supposed to get one before I download?
So AOL have given you plenty of excuses to abandon you shopping cart.
Next!

Mon dieu! You mean it didn't just start the download? Am I an upgrade or a new user? OK, let's go to 'new user'.
Note the sidebar — AOL are positively inviting you to abandon the download and go sniff around some of their other stuff.

Phew! They want my mother's dog's date of birth before I can
download it and try it? Luckily I'm a 102 year-old Swiss woman today.

Um, except Switzerland apparently comes between "Congo" and "Cote D'Ivorie". I guess AOL forgot to pay the license fee for the advanced sort option when they bought in SQL Server. Naturally, "Germany" comes right before "Djibouti", too. I'll bear that in mind. (I couldn't find the UK, anyway.)

Nooooh! It can't be true! But I love you — I want to give you my
life story, hold and caress your IM product in my hand! Don't leave me
now…
MSN Messenger
So, AOL was an embarassing user experience catastrophe. Can MSN do better? At least the rabbit hole has a sign, even if painted somewhat obscurely:

Click on…

OK, so what do I do now? The top of the
screen is animated, and marquees through their key products (Hotmail,
Messenger, Spaces) each with their own "learn more" button. So one
usability problem is that if it switches just before you click, you get
the wrong product.
Anyhow, we wait for "Messenger" to be shown, and click…

Oops! Just takes me right back to the same page, minus the fancy
graphics. Maybe they never tested their web site with Firefox?
Let's go back and click on that "MSN Messenger" text link…

Err, where do I go now? What am I supposed to download? Abandon ship, I think.
Yahoo! Messenger
I think our friends from Sunnyvale can do better, don't you?

The good news: a prominent icon, clearly labelled. And you can even tell that it lets you talk!

OK, since the icon didn't set up the
expectation of a download starting, they've got to stick an
intermediate screen in. Note the lack of clutter and diversions.
Download, learn more, nothing else.

Uh oh! Which one should I choose? Is there anything good — or
missing — in the UK version? I think I'd get a call from my mum at this
point. Remember, a lot of newbies are really afraid of making mistakes.

Cool. Simple download instructions. Although I'm not sure that the
idea of saving to your desktop is going to be universally understood.
All in all, high marks to Yahoo!. A force to be reckoned with?
Skype
So, on to the masters of the slick download.

Subtle? No way! But effective, absolutely.

It's good. It tells you what to do without any jargon. I think they
can do better, though. I should get instructions perfectly tailored to
my browser, not just generic Internet Explorer instructions.
Scores on the doors
You would have thought that by now the traditional IM networks would
have got this process down to a fine art. But clearly not. Marketing
clutter, technical faults, invitations to abandon ship. These are
cumulative. Someone isn't doing their job. (That said, it could be
worse. Ask your mother to provision herself with an open SIP softphone and establish a public identity. Ouch!)
There are lots more bits to the Skype adoption puzzle that make it
sweetly special. The greater degree of internationalisation. The lack
of use of the registry, so it'll install on locked-down corporate
laptops. The fact that incoming calls ring, triggering a Pavlovian
"answer the call", rather than popping up an obscure dialogue box. And
so on.
The only mystery is why Yahoo! is the only one rising to the challenge of out-distributing Skype. AOL were
once the kings of distribution, via CD carpet-bomb. Microsoft outran
them by bundling with Windows, a superior distribution strategy. Yet
neither can get the basics right of a simple download of their most
personal, sticky and vital communications tool.
Until the competition starts putting the user front and centre in
the experience, and not bizdev marketing deals or internal product
marketing struggles, Skype will continue to sweep up new users faster
than the opposition.
via Telepocalypse