[General Topics] Menneisyys:
1.1 The two types of connectivity: SMS and constant Internet connection

There are two main ways a Windows Mobile client can receive instant messages (not counting in Push Mail, which I’ll elaborate on in a later article): either through a constant Internet (for example, GPRS, EDGE, UMTS or HSDPA) connection or via SMS messages. Both approaches have their advantages and disadvantages.

1.1.1 Constant Internet connection

This communication form is far more common with Windows Mobile clients. It requires a constant (!) Internet connection between the mobile device and the service. It has the following advantages:

if you don’t have an unlimited text plan, SMS-based notification can become REALLY expensive as it uses one outgoing SMS for each message you send out. What is more, the 160-character size of SMS messages applies here too – if you enter too “long” messages (more than 150-160 chars), you end up having to pay for two SMS’es and so on. Also, you’ll probably be charged for incoming messages (they arrive as SMS messages) too. Finally, compared to the ubiquity of unlimited text plans, (close to) unlimited data plans are far more common and subscribed to by most Windows Mobile users.

all current, generic IM clients support data connections, unlike SMS messages - SMS support is very scarce with today's clients

It has, on the other hand, some severe disadvantages:

if your data plan isn’t unlimited or, at least, 10-60 Mbytes (depending on the client you use – there are vast differences in bandwidth usage, as we’ll also see) a month while you do prefer having IM on the entire day long, you will soon use up your Internet plan.

battery consumption because of the constant data consumption, particularly with 3G or 3.5G-capable (that is, not just 2.5G GPRS/EDGE) mobiles like the HTC Universal, the TyTN / Hermes, Trinity and the like. 3(.5)G UMTS / HSDPA connections REALLY chew through your batteries QUICKLY. (Note that constant data connection also requires actively waiting for incoming messages in a non-suspended case. This, with current Windows Mobile phones, isn’t a problem, unlike with old(er) Windows Mobile devices not sporting built-in phones. The latter consume a LOT of power in non-suspended case and are hardly usable in day-to-day IM situations if you can’t regularly recharge them.)

For example, in this XDA-Dev thread, XDA-Dev forum members complain about the mobile’s completely chewing through the battery in three hours (!) on the TyTN / Hermes while using Agile Messenger (one of the IM applications available for WM). With a GPRS/EDGE connection, the battery lasted at least eight times more (24 hours).

Fortunately, you can easily fight this problem. As has already been pointed out, it’s typically with high(er)-speed, new-generation connections (UMTS or HSDPA) that the battery consumption becomes really an issue with most current WM-based phones, you may want to force your otherwise UMTS / HSDPA-capable phone to stay at GPRS or EDGE and, consequently, consume way less power. There is even a tool, BandSwitch, to do the trick for you, developed by the excellent XDA-Developers gurus. Please see this thread for more info. (Additional info for example here and here.)

finally, current data connection-based clients can be pretty unreliable. Either they disconnect and, for some reason, fail at reconnecting to the service or are seemingly connected but still don’t receive (send) anything. The latter is the worst possible situation because your party won’t even notice you aren’t receiving her or his messages.

All in all, if being able to be reached all the time and with 100% confidence is of EXTREME importance or you have a Windows Mobile phone with high battery consumption or you have an unlimited text plan, you may want to have a look at SMS-based solutions. Otherwise, stick with data-based ones.

1.1.2 SMS

Now that we've seen the advantages and disadvantages of SMS-based solutions, let's move on to the question of the SMS-capable clients themselves.

There are few clients to support SMS-based messaging. The most important of them is the now-discontinued (and, therefore, not any more recommended), well-known VeriChat.

There are, however, some alternatives you may want to check out:

SMS Threader - v1.17 (also see this)

Palm’s well-known SMS threader application is also worth mentioning. Unfortunately, it's only available for the Windows Mobile-based Treos.

The built-in AIM client in the HP iPAQ h6315, which also used SMS messages (see this and this), while the old one didn’t use SMS’es.

The same stands for the AIM messenger coming with the T-Mobile MDA

Finally, PocketICQ is also SMS-compliant.

1.2 Available Windows Mobile IM clients

As with most of my roundups, this one also contains most of the relevant information in the self-standing comparison chart (CLICK THE LINK!). This is why I don’t list the (missing) features, pros and cons of each and every application in here. If you do spend some time on browsing the chart (make sure you maximize the browser window when you do it so that you end up having to scroll only rarely), you get a very compact, albeit much more useful way of directly comparing all the alternate clients.

Note that there are a lot of features current IM applications offer you may have never even dreamt of (for example, file transfer, voice chat or chatrooms / groupchat). This is why it’s essential you thoroughly scrutinize the chart and the explanation. In order to keep the article as terse and non-self-repeating as possible, it’s only there that I elaborate on these features, not anywhere else. (Now, just imagine I had listed on all the (missing) features of all the reviewed & compared applications in the current article, in free textual form! Not only would it take you ages to even read them all, but also comparing these features to those of the alternates would be WAY harder.)

1.2.1 Webmessenger Mobile Instant Messenger for Pocket PC 2003 2.6 build 070216 (a WM5-only version, “Mobile Instant Messenger for Windows Mobile 5.0”, is also available here)

This is a comparatively new product with pretty average features. The developers also offer two other, mostly enterprise-targeted (for example, Jabber support) IM solutions.

It's the only IM app for WM to support Skype (in addition to the "official" Skype client, of course). However, this requires an additional plug-in: you must also register for at least the free version of WebMessenger Mobile for Skype. Make sure you download the desktop component as well.

1.2.2 IM+ 4.3 by Shape Services

This is one of the most widely used and known, well-established, leading IM solutions. Should be one of the products you take a very serious look at.

Review here; a generic thread is here; another one thread on some recent (4.28, 4.29) bugs.